Question

Find the area of circle whose radius is 7cm

Answer 1

Area of a circle in terms of radius:

Area = π·r2 = 3.14·72 = 153.9 square centimeters(*)

Area of a circle in terms of diameter:

Area = π·(d

2

)2 = 3.14·(14

2

)2 = 3.14·(7)2 = 153.9 square centimeters(*)

Area of a circle in terms of circumference:

Area = C2

4π

= 43.982

4π

= 1934.24

(4·3.14)

= 1934.24

12.56

= 153.9 square centimeters(*)

(*) 153.9380400259 centimeters, exactly or limited to the precision of this calculator (13 decimal places).

Note: for simplicity, the operations above were rounded to 2 decimal places and π was rounded to 3.14.

Answer 2

Answer:

Question

Find the area of circle whose radius is 7cm

Solution

$area \: of \: circle \: = \pi {r}^{2}$

$= \frac{22}{7} \times 7 \times 7$

$22 \times 7$

${154}^{2} cm$

Extra information

Area of rectangle= l × b

Area of square = side × side