10-210-2Areas of Trapezoids, Areas of Trapezoids, Rhombuses & KitesRhombuses & Kites

Objective:Objective:

To find the area of a trapezoid, To find the area of a trapezoid, rhombus or kiterhombus or kite

Essential UnderstandingYou can find the area of a trapezoid when you

know its height and the lengths of its bases.

Review Terms & FormulasArea

Base

Height Theorem 10-2 Area of a Parallelogram

Theorem 10-1 Area of a RectangleA=bh

A=bh

bhA21

Theorem 10-3 Area of a Triangle

b

h

b1

b2

h

Theorem 10-4 Area of a Trapezoid

The area of a trapezoid is half the product of the

height and the sum of the bases.

hbbA )( 2121

3cm

9cm

4cm

What is the area of a trapezoid with height 4cm and bases 9cm and 3cm?

hbbA )21

(21

4)39(21 A

224cmA

Theorem 10-5 The area of a Rhombus or a KiteThe area of a rhombus or a kite is half the product of the lengths of its diagonals.

Theorem 10-5 The area of a Rhombus or a KiteThe area of a rhombus or a kite is half the product of the lengths of its diagonals.

2121 ddA

How can I find the area of a rhombus or a kite?

ExamplesFind the area of each figure.

3 in

8 in

2 m

1 m 4 m

p. 626: 11-25, 29, 31

A = 12in2

A = 10m2