Area of Parallelograms, Triangles and Trapezoids

1
Area of Parallelograms, Triangles and Trapezoids
2
5 in
4 in

• What is the area of the parallelogram?
• Area base times height
• Area b h
• A 5 in 4 in
• A 20in2

3
Triangles
height
base
The area of a triangle is ½ the area
of a parallelogram. Area ½ base x height A ½
bh
4
Find the Area of the Triangle

• A ½ bh
• A ½ (6.5m) x (10m)
• A ½ (65m)
• A 32.5 m²
• To take half you can divide by 2 or multiply
  by 0.5

10m
6.5m
5
Find the Area of the Triangle

• A ½ bh
• A ½ (14ft) x (11ft)
• A ½ (154ft)
• A 77 ft²

14ft
11ft
6
Find the Area of the Triangle

• A ½ bh
• A ½ (8mm) x (9.6mm)
• A ½ (76.8mm)
• A 38.4 mm²

8mm
9.6mm
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Trapezoids
b
1
h
b
2

• A trapezoid has two bases, b and b . The
  height (h) of a trapezoid is the distance between
  the bases.
• A ½ h( b b )

1
2
1
2
8
Find the Area of the Trapezoid
12 in

• A ½ h( b b )
• A ½ (7in)(5in 12in)
• A ½ (7in)(17in)
• A ½ (119in)
• A 59.5 in²

1
2
7 in
5 in
9
Find the Area of the Trapezoid
7 ft

• A ½ h(b b )
• A ½ (8ft)(7ft 15.6ft)
• A ½ (8ft)(22.6ft)
• A ½ (180.8ft)
• A 90.4 ft²

1
2
8 ft
15.6 ft