Question

The area of a circle is 1386m2. Find its circumference?
fog?
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Answer 1

Answer:

$\large\mathrm\purple{Given:} \:$

$\mathrm{Area \: of \: circle = 1386 m^2}$

$\large\mathrm\purple{To \: find : } \:$

$\mathrm{circumference \: of \: the \: circle = ? } \:$

$\large\mathrm\red{solution : } \:$

$\fbox{Area \: of \: circle = πr^2 } \:$

$\fbox{π = \frac{22}{7}}$

$\mathrm{1386 = πr^2} \\ \\ \implies \mathrm{1386 = \frac{22}{7} \times r^2} \\ \\ \implies \mathrm{1386 \times 7 = 22 \times r^2} \\ \\ \implies \mathrm{9702 = 22 \times r^2 }\\ \\ \implies \mathrm{\frac{9702}{22} = r^2} \\ \\ \implies \mathrm{441 = r^2} \\ \\ \implies\mathrm{ \sqrt{441} = r} \\ \\ \implies \fbox{21= r}$

Hence the radius is 21m.

$\mathrm{Perimeter \: of \: the \: circle = 2πr} \\ \\ \implies \mathrm{2 \times \frac{22}{7} \times 21} \\ \\ \implies \mathrm{ 2 \times 22 \times 3 } \\ \\ \implies \fbox{ 132 m} \:$

Hence the perimeter of the required circle is 132m.