6.4 Area Learning Objectives: 1. Find the area of geometric figures: rectangle, square, triangle, parallelogram, trapezoid, circle. 2. Key Vocabulary: area, square units. Area Formulas of Common Geometric Figures 1. Rectangle 2. Square W A = LW s A = s2 L
3. Triangle 4. Circle 1
r
A = bh A = πr 2 2
h d
b 5. Parallelogram 6. Trapezoid b
h 1
A = b⋅h
A = ⋅ h ⋅ (B + b )
h
2
b
B
Unit of area: Note: Do not use π = 3.14 ft.2 , m 2 , cm 2 , yd 2 , in.2 , . . . . . Example 1. Find the area of the following. 1. 5.5 km 4.5 km
10 km
12 km
2. 2.2 ft.
1
4 ft.
2
3. A small rug is in the shape of a trapezoid. The bases measure 19.8 in and 22.4 in. and the height is 8 in. Find the area of the rug. Read: Sections 6.5