1.7 composite figures (1)
- 1. 1.7 Composite Figures • A composite figure is formed from two or more figures. To find the area of a composite figure: • Find the areas of each figure then add them up. • To find the area of a shaded region, you need to subtract the areas. Sept. 4!
- 2. Example #1: Find the area of the composite figure. The composite figure contains 2 triangles and 1 square. We need to find the area of each region. Area of 1 triangle: A = ½ bh A = ½ (7)(4) A = ½ (28) A = 14 yds2 Area of square: A = lw = 7(7) = 49 yd2 Total area of figure: Add up areas of 2 triangles and square: A = 2(14) + 49 = 28 + 49 = 77 yd2.
- 3. Example #2: Find the area of the figure. The figure contains: 1 square and a semicircle Area of square: A = lw = 6(6) = 36 ft2 Area of circle: A = r2 A = (3)2 = 9 ft2 Area of semicircle = ½ (9) = 4.5 ft2 3 ft. Total area of figure: Add areas of square and semicircle: A = 36 + 4.5 cm2
- 4. • Example #3: Find the area of the shaded region if the area of the square is 64 ft2. • We are given the area of the square, we need to find the area of the circle. • What is its radius? • Diameter = Length of square = = 8 ft. • Radius = ½ (8) = 4 ft. • Area of circle: • A = r2 • A = (4)2 = 16 ft2. 64 • Area of shaded region = • Area of square – Area of circle • A = 64 - 16 ft2. d = 8 ft.
- 5. QUIZ Show your work! 1. Find the area of the entire figure below. 20 cm 2. Find the area of the shaded region above.