Wednesday, April 3, 2013

Properties of an isosceles trapezoid

What are the properties of an Isosceles Trapezoid? Let’s look at a list of the properties.
1. It is a quadrilateral so a trapezoid has four sides.
2. A trapezoid has one pair of parallel sides. When you look at shapes in Geometry arrows are used to indicate that two sides are parallel.
3. An isosceles trapezoid has one pair of congruent legs. Therefore, one pair of legs will be the same length.
4. The bases in an isosceles triangle are parallel, and the legs are congruent.

 5. The interior angle measure of an isosceles trapezoid will equal 360 degrees and the adjacent angles are supplementary. If you look at the picture below, angles w and x are congruent and angles z and y are congruent. In addition angles w and z are supplementary and angles x and y are supplementary.

6. The formula for finding the perimeter is equal to P = b1 + b2 + S1 + S2  ( see picture)
7. The area of a trapezoid is A = ½(b1 + b2)h  ( see picture )

Please watch the to see the properties of a trapezoid explained.

For more information please see What is a trapezoid
For a list of perimeter formulas Perimeter Formulas Plane Shapes