In which quadrilateral are the diagonals always congruent and why?

Question

A. Rectangle

B. Trapezoid

C. Rhombus

D. Parallelogram

Answer 1

First it is good to draw each shape.

from the drawings, which diagonals look equal.

note, not all trapezoids are isosceles. A rhombus is a slanted square, and a parallelogram is a slanted rectangle

Answer 2

The answer to the WHY question is best seen by using congruent triangles or the Pythagorean theorem.