None of the pairs will deliver (g×f)(a). If you intend (g∘f)(a), then ...
... selection 3 is appropriate.
It's a parallelogram so if one angle is 90 degrees they all will be because of transverse angles and all that good stuff.
So we're given the diagonal of a rectangle and one side and we're asked to find the other. The diagonal of a rectangle is the hypotenuse of the right triangle whose legs are the sides of the rectangle. So this is a Pythagorean Theorem question in disguise:




Answer: 140 cm
I don't recall seeing this Pythagorean Triple before.
Answer:
a parrellelogram is a rectangle T^T
just that they slanted it.
UNSLANT IT.
if that makes sense.
Not if it ends at 9, like you typed it.
I have no idea sorry I wish I could help but!♀️