Trapezoids: Finding Angles and Segments.

Do you know that when you have an isosceles trapezoid: All acute angles are congruent, all obtuse angles are congruent, and that if you take one acute, and one obtuse at a time they are supplementary?

In this lesson, you will work with isosceles trapezoids. You will view the solution of the problems with an emphasis in highlighting the concepts from previous sections that apply to this type of problems. You will be given a few problems embedded in the lessons to test your understanding. Venture yourself to a new trapezoid experience!

Lesson's Content

Lesson's Glossary

Angle
Geometry shape formed by two rays (initial and ending sides of the angle) that share a common endpoint called the vertex. You may name an angle using the vertex, or a point in each ray and the vertex label in the center.

Isosceles trapezoid
Trapezoid with two non-congruent and non-parallel sides. 

Polygon
It is a closed plane figure with a least three straight segments as sides.

Quadrilateral
A four-sided polygon.

Segment
Line segment; A section of a line, defined by two end points and all the points between them.

Trapezoid
Quadrilateral with exactly one pair of parallel sides.

Interactive Geometric Applets: Relevant Theorems.

In an Isosceles Trapezoid opposite angles are supplementary, it has only one pair of parallel sides,

and one pair of congruent sides. Diagonals are congruent, but they don't bisect each other.

This interactive geometric applet will allow you to visualize these properties in a dynamic

way.

When working with isosceles trapezoids the parallel segments form

consecutive interior angles that are supplementary. You may review this property

for parallel lines cut by a transversal.

Drag point "B" in the below applet to verify this angle relationship.

Vocabulary Puzzle Interactive

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