Question

the circumference of a circle is 31.4 cm find its area​

Answer 1

Answer:

since, circumference=2πr.(we take value of π=3.14)

so, 2×31.4/3.14=. 62.8/3.14

=628×100/314×10. since,removing decimal.

=6280/314=20. r=20

hence,area of circle = πr square.

22/7×20×20=22/7×400.

8800/7=1257.14 is your ans.

Answer 2

Answer:

given

2πr=31.4

r=31.4/2π

r=31.4/2*3.14

r=5cm

therefore area of triangle =π(r^2)

$3.14 \times 5 ^{2} =3.14 \times 25 = 78.5 cm^{2}$