Question

Find the circumference of a circle whose area is 1386 cm².
(A) 132 cm² (B) 132 cm (C) 42 cm (D) 21 cm²

Answer 1

hey dear
here is your answer

area of a circle =
$\pi {r}^{2}$
$1386 \: = \pi {r}^{2}$
$1386 \: = 3.14 \times {r}^{2}$
${r}^{2} \: = 441$
$r \: = 21 \: cm$
now, circumference of a circle =
$2\pi \: r$
$2 \times 3.14 \times 21 \: = 131.88 \: cm \\ = 132 \: cm$
hope it helps :)

Answer 2

Area =pi*r²
1386=22/7*r²
1386*7/22=r²
441=r²
21cm²=r


Circumference =2pi*r
2*22/7*21
=132cm²



hence option (a) is correct