Page 143 - NUMINO TG_6A

Activity 1 Areas of Circles

jOb ective Find the area of a circle.

1. Textbook Instructions Activity 1 Areas of Circles

Have the students use the formula for the Learn how to find the area of a circle.
area of a circle to solve for each area.
Area of a circle 6 cm Area of the circle = π radius radius
3.14 6 6
area of a parallelogram 113.04 (cm2)
base height
half the circumference radius 1 . Find the area of each circle. 10 in c.
(π radius 2) 2 radius
π radius radius a. b. 16 m
3.14 radius radius
5 cm
1. Have students memorize the formula to
find the area of a circle. 78.5 (cm2) 314 (in.2) 200.96 (m2)
3. 14 8 8 200.96 (m2)
1a, 1b, 1d, 1e. d.
When the radius is given, e. f.
(Area of circle) 3.14 (radius) (radius). 7 ft
28 yd
1c, 1d. 153.86 (ft2)
If the diameter is given, find the radius, and 76 11 cm
then use the formula,
(Area of circle) 3.14 (radius) (radius).

379.94 (cm2) 615.44 (yd2)
3. 14 14 14 615.44 (yd2)

2. Build Understanding

Problem: Complete the table using the circles and find the areas.

a. 9 cm b. Circle Radius Formula Area
a
32 in.

b

Answer: Circle Radius Formula Area
a 9 cm 3.14 9 9 254.34 cm2
b 16 in. 3.14 16 16 803.84 in.2

126 NUMINO Teacher s Guide