Question

What is the length of the missing side?

16 mm
28 mm
42 mm
69.5 mm

Answer 1

It's a right triangle, so the length of (unknown side)^2 + 45^2 = 53^2.

Answer 2

let x be the missing side
by pyth.thm.,
53^2 = 45^2 +x^2
x=28mm