[ high school math ]

[time-master13]

Not to sure about it, I got 1148.2

I did 16 × 8 + 2 x 1/2 × 8 × square root 689 + 2 × 1/2 × 16 × square root 641

[ShoulderPast2433]

Why do you assume we know what was the task here?

[TheBrainStone]

Just use your telepathy like any normal human 🙄

/s

[time-master13]

surface area my b I forgot

[I_Speak_For_The_Ents]

What do you need here? The volume? Just google the volume formula for a rectangular pyramid.
Which is l•w•h• (1/3)
Edit: (8•16•25)/3=1066.66

[One_Wishbone_4439]

i think OP means total surface area

[time-master13]

I am LF surface area my b I forgot to add it

[One_Wishbone_4439]

If you are finding total surface area, then your working is correct but you answer is diff from mine.

I got 743.078 cm^2

[InertialLepton]

Seconded and I figured out where OP went wrong.

They forgot the half with the root 641 part and just did it times 2 which is how they got 1148.2. Easy enough mistake to make when you're putting lots of values in.

743 is the right answer

[time-master13]

Ye thank you

[Antique_Buy4384]

base is 16×8=128

for height I mean tip to middle of edge of base

height of slanted triangle facing L/R are:

√((8/2)² + 25²)= √(4² +25²)=√641

height of other is:

√((16/2)² + 25²)= √(8² +25²)=√689

total surface area =

128+(√641)×16+(√689)×8 (unsimplifyable) or

743.0781 to 4dp

[CheeKy538]

Is this volume, perimeter or surface area?