Question

(i) the circumference of a circular flower bed is 88 cm. find its area.
(ii) the area of a circle is 15400 m square. find its circumference

Answer 1

circumference

C =2πr

88cm=2×22÷7×r

88×7÷22×2=r

r=14cm

area=πrsq.

=22÷7×14×14sq.cm

=616sq.cm

For the given Area:

Given area of circle = 15400 sq m

That is pr2 = 15400

(22/7)r2 = 15400

r2 = 15400 ´ (7/22) = 4900

r = 70 m

Circumference of circle = 2pr

                                     = 2 ´ (22/7) ´ 70

                                     = 440 m

Answer 2

1) circumference=2 pi r =88 Pi r =44 Pi r^2=x r = 44×7/22 r =14 Pi r^2=22/7×14^2 =616  2)pi r^2=15400    2 pi r=x    22/7×r^2=15400    r^2=15400×7/22    r^2=4900    r=70  2 pi r=2×22/7 ×70 2 pi r =440 Circumference=440