Answer:
Explanation:
To prove that the diagonals of an isosceles trapezoid are congruent, we will first define the terms and draw a diagram of the isosceles trapezoid.An isosceles trapezoid is a quadrilateral with two congruent legs, a pair of parallel bases, and congruent base angles.Let's call the isosceles trapezoid ABCD and let the parallel sides be AB and CD, and the congruent legs be AD and BC. Let the diagonals be AC and BD.Since, AD and BC are congruent legs, therefore ∠BAD = ∠CAD by the definition of congruent legs.And since ABCD is a trapezoid, therefore, AB || CD and therefore, ∠BAD = ∠CBD, due to alternate angles are congruent.Therefore, ∠CAD = ∠CBD, by CPCTC (corresponding parts of congruent triangles are congruent)AC = BD , since both are congruent by ASA (angle-side-angle) congruence.Thus, the diagonals of an isosceles trapezoid are congruent.