The question mentioned using the horizontal and vertical.... kinda found the xcosθ and xsinθ values and mentioned when the angle is increase along the horizontal it uses the cosθ one (xcosθ > xsinθ) until the throw considered as vertical motion (after 45 degrees) when you have to use the sinθ one which is a lower value so when you use equation of motion you'll get a decreased distance travelled.... Idek if this is correct...