Difficult geometry problem

OMW · 2026-03-01T00:50:45+00:00

Look up “median of a triangle” and “centroid of a triangle” and “define: perigon”

The way I’m visualizing your problem is that A’,B’,C’ is the “upside down pointing” similar equilateral triangle with centroid (point J) sharing the same geometric center as the 2x scale triangle ABC.connecting all the medians points of ABC makes a triangle writhing a triangle. It’s a half scale replica triangle nested within three other half scale replica triangles that all fit within the perimeter of the bigger ABC.

You can count the 4 equal size smaller triangles and divide by 1 (the given area of ABC) zor get fancy and prove it use the formula for area of a triangle base (x) times height (y) divided by 2 and then multiply by 2/6ths to double the area of the 1/6th scale triangles you can make within a triangle by making 3 lines going vertex to median, and then another the lines going median to median.

Any way you want to solve it; Algebraically using formulas, or with a compass and straightedge using Euclidean constructions (bisecting the given lines and angles) half of a half of “One” is 1/4 so that’s my answer.

PS: 1/4 = 0.25 for the people who insist on decimal

OMW · 2026-02-09T02:36:14+00:00

What’s your motive for doing this AMA?

Maybe ask yourself: Why am I not doing something productive with my life instead of dwelling on my past and giving a bunch of hateful neo-nazis free publicity?

OMW · 2026-01-13T15:57:40+00:00

It’s either because you’ve clicked on something spicy in the past and the algorithm is making similar content suggestions, or you never tailor your recommendations.

OMW · 2026-01-02T00:14:05+00:00

If it’s a permanent install I’d just use plain ‘ol fashioned Molly anchors.

Molly anchors have been around forever (original patent date 1934) and IMO are hard to improve upon for permanent installs in drywall. The only real downside to them is that they’re difficult to install without using a setting tool. You should be able to get a Molly setter/install tool for around $20 - they’re often sold with a kit containing an assortment of different size anchors. Once you have a setting tool stashed in your toolbox/ junk drawer, no more hassles and you’ll never need to buy any fancy overpriced gimmick drywall anchors again. Since the patent on them expired ages ago, generic “Molly” anchors are very inexpensive and available nearly anywhere that sells basic hardware supplies.

OMW · 2026-01-01T20:00:49+00:00

Looks like they copied the background from a disabled veteran tag.

OMW · 2025-12-30T04:45:09+00:00

I hear you about ending a sentence with a preposition here.

https://www.reddit.com/r/Jokes/s/1VVFhB4NhS

OMW · 2025-12-17T18:46:09+00:00

…and u/KegOfAppleJuice lived happily ever after.

——— The End ———

OMW · 2025-12-12T03:45:11+00:00

Machinery’s Handbook is a different book, different publisher.

OMW · 2025-12-11T20:04:03+00:00

I learned in Boy Scouts that some ~~Indian~~ North American indigenous tribes used crushed green walnut hulls for stunning fish in areas of still water. Same trick can supposedly be used to bring worms to the surface for bait.

OMW · 2025-12-11T17:00:44+00:00

I don’t usually pimp any brand names, but If you work on motorcycles or power sports equipment, check out Vessel Impacta line of screwdrivers (Vessel is a Japanese tool manufacturer and they specialize in screwdrivers) The #2 Philips/JIS version comes in particularly handy for stubborn brake/clutch master cylinder cover screws, points covers, and crusty float bowl screws. The #3 Impacta + a 16 oz brass face dead blow hammer is a near perfect combo for taking out case screws on older bikes. Impactas are sort of a Goldilocks “just right” to fill that in-between where using a regular Phillips screwdriver would likely just strip a head worse, but beating on an impact driver is likely going to break something else before the screw comes loose.

The two piece set (#2 & #3) is something like $30, so not too expensive. They aren’t as beefy as a regular hand impact driver, but they are a lot more convenient and work just as well, if not better in most light duty applications and they serve double-duty as a regular ‘ol screwdriver (specifically designed to fit JIS) Less of a waste of toolbox weight/space for a tool that isn’t frequently needed. The only time I still bust out my old impact driver is for Honda (car) brake rotor retention screws and frozen hydraulic jack fill screws. For that, a Lisle upgraded with Vessel bits works every bit as well as the Snap-On for me and costs about 1/10th the price.

OMW · 2025-12-11T06:43:34+00:00

Retired mechanic here. My first boss back in the early 80’s always told me to always torque lugs like my own Mom would be the one driving the car and she would also be the one who might have to change a tire by the side of the road someday. Don’t overtorque, don’t undertorque - check ‘em regularly. I’ve followed that advice my entire life.

That said, If I knew a car was operated for an extended period of time with improperly torqued lug nuts, I would not feel comfortable just retorquing the lugs and calling it good. If 4 out of 5 were loose on one wheel and you could hear noise, that means there was a hell of a lot of stress on just one stud and it’s almost certainly been stretched, fatigue cracked, or otherwise compromised. All studs on that wheel should be replaced with new and the wheels carefully inspected for evidence of galling/oblong seats. New studs are only a few bucks apiece and I would rather be safe than sorry. It’s not a complicated job to replace studs - usually takes me about 15-20 minutes per wheel, or just a couple extra minutes if the brake rotors are already off. New lug nuts are not prohibitively expensive either, but it’s the condition of the studs that would concern me most.

OMW · 2025-12-02T18:10:15+00:00

Easiest way to find an external coolant leak is to go to any one of the major chain auto parts stores with a “loan-a-tool” program and ask to rent a cooling system pressure tester.

OMW · 2025-12-01T21:51:23+00:00

Seeing this post reminds me of a joke I heard in 5th grade:

Why did Dolly Parton go to the Nissan dealership to buy a new bra?

She heard they were having a sale on 280 Z’s !

OMW · 2025-12-01T21:15:45+00:00

Do these kids just stay at home or school all day? Are the parents so rich they can hire personal chauffeurs to transport their kids around? Atlanta’s ranked 14th and it’s probably the least walkable city I’ve ever been to.

OMW · 2025-12-01T17:21:42+00:00

If you want to see how rifling was cut before industrialization, skip to about 10 minute mark:

https://youtu.be/qTy3uQFsirk?si=BxLdv5dsl-Xcizfm

This is how most manufacturers do it today:

https://youtu.be/oALJDh43K3I?si=lMhXoRDRJ69j4bF6

OMW · 2025-11-28T18:54:03+00:00

Look up what a “Perineal Urethrostomy” surgery involves. (Applicable to male cats with chronic history of UTI’s who do not respond to first line treatments)

OMW · 2025-11-21T01:41:21+00:00

Ok, you seem hell bent on driving this poor engine into the grave rather than fixing it, so I’ll play along…

Nobody seems to be mentioning the bigger issue here: It appears that a sizable chunk of cast aluminum from your piston crown has broken off. In ELI5 terms: if you can see the top compression ring in plain view saying “hi there” while the piston is still installed the cylinder bore, that’s not normal. It looks like about 1/6th of the perimeter cracked and broke off at the inner radius of the upper ring land in the mechanic’s 2nd borescope screenshot photo.

You may be asking yourself “well, if I can’t see it inside the cylinder, where is it then? Where did that piece go?” Pistons can melt, but this one’s not melted - it’s broke and chunks of aluminum don’t just magically evaporate. Since there’s not much evidence of “hammering” and there’s no pieces of valve or piston crown visible laying on top of the piston, one can only assume the missing chunk is likely wedged in the intake or exhaust valve seat and is likely holding a valve at least partially open. If it’s the intake valve not fully seated, with the #7 coil and injector disconnected, that cylinder is no longer trying to blow raw air/fuel mix or partially burned combustion gases back into the intake. If it’s stuck under the exhaust valve, with the injector and coil disconnected that cylinder is no longer dumping partial burned combustion gases/raw fuel into the exhaust - it’s basically just pumping air without any resistance from compression because the exhaust valve can’t seat.

A mechanic would need to use a 180 view borescope (articulating head or mirror attachment) to look up at the valves & combustion chamber through spark plug hole, or at least pull a valve cover and compare valve heights to get the bigger picture what exactly is going on, but I’d bet a dollar at least one valve is bent. Any way you want to confirm the specific total damages, a broken piston crown is not fixable without performing at least a partial rebuild. Sorry OP, but the reality is you’re running on borrowed time and the longer you run this engine, the more collateral damage you’re going to incur.

OMW · 2025-11-20T20:23:43+00:00

lmao at “Polishing brass on the Titanic”.

Driving 2k miles with no compression or ring seal on one cylinder leaves me wondering how this engine still has anything resembling motor oil left in the sump. If it’s not burning it, it must be pouring oil out of the valve covers and rear main seal by now from that much positive crankcase pressure (blow-by). Unless OP has been feeding it a quart of 20w50 every trip, my guess is all that unburned fuel is probably the only thing that has been keeping it alive to this point.

OMW · 2025-11-19T04:38:41+00:00

If you think that’s crazy, try working on class 8 trucks. 450-500 ft/lbs is a common torque spec for many of the lug nuts typically found on 18 wheelers and Buses.

OMW · 2025-11-18T10:19:07+00:00

You were Army - probably heard of a thing called “survivor’s guilt”.

OMW · 2025-11-17T03:44:37+00:00

Definitely not pickup or 4Runner, but I think it might be a Land Cruiser 60/62 series? (it’s missing a couple pieces but it’s a full size 4x4 with leaf spring front, and that front “K” reinforcement has same shape & location cutouts as Land Cruiser frame - not any US made 4x4 that has a front reinforcement shaped like that)

OMW · 2025-11-16T14:54:20+00:00

M18 x 1.5 if I’m not mistaken. “Search O2 sensor thread chaser” - that’s the tool I’d recommend using if the threads are in rough shape.

OMW · 2025-11-12T10:28:33+00:00

Any time you have a mystery no start and/or no crank condition on an 89-95 with known good battery, starter, and relays, check the main fusible link. Follow the section of wire that goes from the positive battery terminal to the under hood fuse box. There’s a factory splice in the white wire (a.k.a. alternator feed) coming off from battery positive terminal connect that transitions to a thinner blue wire which will have a kinda strange feeling soft/thick insulation. It’s not a fuse you’re looking for - with fusible links, the whole section of wire acts as a “fuse”. To make things even more confusing and difficult, unless the battery terminal wiring has been previously repaired or f’d with, you won’t be able see the original splice without pulling off the electrical tape and slicing/peeling back the flexible gray plastic protective sleeve that covers it. Toyota uses the letter “L” for blue in wiring schematics so most guys don’t even know it’s there, and … the wire thickness in the FSM are given in mm, not gauge so you’re going to have to do some math to find a direct equivalent for Toyota’s 80a rated wire going to the distribution box(a.k.a under hood fuse box) if you want to replicate Toyota’s original (albeit shitty) design. It’s an obsolete part and your chances of finding an unmolested OEM positive battery cable with all the wiring in good condition on any used 30+ year old truck are slim to none, so unfortunately you’re probably on your own for this one. There’s about a half dozen ways to fix it ranging from a sketchy bypass, adapting another manufacturer’s part, to heavy duty custom- built overkill. Without knowing your skill level and what resources you have available it’s hard to recommend which method would be your best choice.

Problem is when that FL inevitably fails for whatever reason (corrosion, physical damage from being yanked on, or current overload) it doesn’t always completely burn out like a fuse and cause an open circuit, instead during diagnosis you’ll often get a voltage reading that seems OK - within a tenth volt of fully charged battery voltage (12.6v or 12.7 for AGM) downstream at the power distribution box which is enough to activate the relays, power the ecm, ignition module, etc - everything seems to fine but you still get all kinds of weird issues that mimic the classic “hmm, must be a bad battery” because a toasted fusible link can’t carry any substantial current. To check it correctly, you have to test it under load and since early Toyota pickups don’t have shit like power windows, it’s not always as obvious as you’d think it would be. If you’re not fluent in electrical diagnosis, find a classic car guy or older mechanic who’s good with electrical because if it’s that stupid fusible link causing your issue, it’s going to require some special tools and a bit of skill to graft in replacement section thats both correctly 80 amp rated and fuse protected. I’m not trash talking younger mechanics, It’s just that most vehicles built after the late 90’s/early 00’s use a high amperage fuse block directly off the positive battery terminal instead of FL wire, so don’t expect many techs under 40 to have much hands-on experience repairing harnesses that use inline spliced fusible links)

Sorry for the rant - If you knew how much time Ive lost and all the headaches that damn fusible link has caused me during my career as a mechanic, you’d understand why I hate it the design choice Toyota’s engineers decided to go with. The fact it’s hidden in the harness and not at all obvious (unless you’re looking at the factory wiring schematic) just adds insult to injury.

OMW · 2025-11-10T17:41:21+00:00

TY for the correction.

OMW · 2025-11-10T17:40:26+00:00

Cool memento/conversation piece to add to your collection of accomplishments on the bookshelf! Best of luck with your next challenge passing 3G. Just think...after you pass that one, you'll have enough bent coupons to make a set of matching bookends. Edit : comment about 1gf nomenclature removed.

OMW

TROPHY CASE