Page 146 - NUMINO TG_6A

09Transforming It into a Parallelogram Unit

Have students find the areas of the figures to solve each problem, and then find the difference 2. When a part is removed from a figure, the
according to what part is shaded.
area is subtracted from the original figure.
2 . Find the area of the colored parts.
Find the areas of the colored parts.
3 m Area of the larger circle 3.14 5 5 78.5 (m2)
2 m Area of the smaller circle 3.14 2 2 12.56 (cm2) Example: Subtract the smaller circle from

Area of the larger circle Area of the smaller circle the larger circle.
78.5 12.56 65.94 (cm2)
2 cm

5 cm

a.

Area of the circle 3.14 10 10 314 (in.2)

Area of the square = Area of 4 triangles (3.14 5 5) (3.14 2 2)
1 78.5 12.56
10 in = (10 10 2 ) 4 = 200 (in.2) 65.94 (cm2)

10 in Area of the circle Area of the square 2a.
314 200 114 (in.2)

b.

6 cm Area of the quarter circle 3.14 66 1 28.26 (cm2)
Area of the triangle = 6 = 18 (cm2) 4

6 1
2

6 cm Area of the quarter circle Area of the triangle 2b.

28.26 18 10.26 (cm2)

c. Area of the larger semicircle 3.14 4 4 1 25.12 (ft2) 2c.
2
4 ft 4 ft
Area of the smaller semicircle 3.14 2 2 1 6.28 (ft2)
2

Area of the larger semicircle Area of the smaller semicircle

25.12 6.28 18.84 (ft2)

9. Transfoming It into a Parallelogram 79

Problem: There are 4 equal circles drawn inside a square with a length of 20 m. 20 m
Find the area of the colored part. 20 m

Solution: Subtract the white shapes from the area of the whole figure. 6A Unit 09 129
Area of the square 20 20 400 (m2)
The radius of each circle is 5 m.
Area of 4 circles (3.14 5 5) 4 78.5 4 314 (m2)
Area of colored part 400 314 86(m2)

Answer: 86 m2