Sec' 10 2 Areas of Trapezoids and Kites

1
Sec. 10 2 Areas of Trapezoids and Kites

• Objectives
• 1) Find the area of trapezoids.
• 2) Find the area of kites.

2
Trapezoids
b1 base 1
h height
leg
leg
Height distance between the 2 bases. Must
be ?
b2 base 2
base
base
Area of trapezoid
A ½ h(b1 b2)
Height
3
Ex. 1 Find the area of the following
trapezoid.
20in
This is the height!!
30in
18in
36in
A ½ h(b1 b2) ½ (18in)(36in 20in) ½
(18in)(56in) 504in2
4
Ex. 2 Find the area of following trapezoid.
This is a 30-60-90 ?
5cm
A ½ h(b1 b2) ½ (3.5cm)(5cm 7cm) ½
(3.5cm)(12cm) 20.8cm2
h
60
7cm
Need to find h first! Short side 2cm h 2v3 h
3.5cm
5
Area of a Rhombus or a Kite

• Rhombus
• 4 equal sides.
• Diagonals bisect each other.
• Diagonals are ?.

• Kite
• Adjacent sides are ?.
• No sides //.
• Diagonals are ?.

Area of Kites or Rhombi
A ½ d1d2
Diagonal One
Diagonal Two
6
Example 3 Find the Area of the following
Kite.
4m
A ½ d1d2 ½ (6m)(9m) 27m2
3m
3m
5m
7
Example 4 Find the area of the following rhombus
d1 24m d2
15m
12m
18m
b
12m
A ½ d1d2 ½ (24m)(18m) 216m2
15m
a2 b2 c2 122 b2 152 144 b2 225 b2
81 b 9
8
What have I learned??

• Area of Trapezoid
• A ½ h(b1 b2)
• Area of Rhombus or Kite
• A ½ d1d2