If a quadrilateral (with one set of parallel sides) is an isosceles trapezoid, its legs are congruent.

Name the shape of the quadrilateral whose diagonals are not equal.

$\mathrm{SIDE}$ is a kite in which diagonals $\mathrm{SD}$ and $\mathrm{EI}$ intersect at point $\mathrm{O}$. Give reasons for the following:

$\angle \mathrm{DEO}=\angle \mathrm{SEO}$

A trapezium is a special kind of quadrilateral whose two opposite sides are parallel but the other two sides are non-parallel.

The opposite sides of a trapezium are parallel.

Identify the following geometrical figure.

In an isosceles trapezium $ABCD$, find the length of $AB$. Give reason for your answer.