Question

The circumference of a circle is 123.2cm.calculate (a) radius of the circle.(b)area of a circle.(c)the effect on the area of the circle if the radius is doubled

Answer 1

Answer:

Circumference = 123.2 cm (2 pie r)

that is 2 × 1/2 × r

a.) r = 19.6079

b.) area = 1,207.846

c.) doubled radius = 39.2158 (diameter)

area = 4831.39

answer↑

Answer 2

Answer: (a) 19.6 (b)1207.5 (c)4825 (area will be 4 times the initial area).

Step-by-step explanation: (a) Circumference of a circle = 2pi.r = 123.2(given) or r=123.2/2x3.14 or r=19.6

(b) Area of circle = pi x r^2= 3.14 x 19.6 x 19.6 = 1207.5

(c) new radius=2 x 19.6 = 39.2

New area = 3.14 x 39.2 x 39.2 = 4825

Effect on area = 4825/1207.5 = 4 times.