Isosceles Trapezoid

An trapezoid with congruent Legs

The defining trait of this special type of trapezoid is that the two non-parallel sides (XW and YZ below) are congruent.

Base Angles

The base angles of an isosceles trapezoid are congruent.

Base Angles of Isosceles trapezoid picture
Problem 1

If you know that angle BAD is 44°, what is the measure of $$ \angle ADC $$ ?

Base angles of isosceles trapezoid problem

Angle $$ \angle ADC = 44° $$ since base angles are congruent

Problem 2

$$ \angle ABC = 130 $$, what other angle measures 130 degrees?

Base angles diagram and problem

Single $$ \angle ADC = 4° $$ since base angles are congruent

Problem 3

What is the value of j in the isosceles trapezoid below?

Base Angles practice Problem

J = 5

Diagonals of Isosceles Trapezoid

Problem 3

The diagonals of an isosceles trapezoid are congruent. What is the value of x below? (use your knowledge about diagonals!)

Diagonals of Isosceles Trapezoid

X = 9

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