Question

Find the area of circle whose-
(i) radius is 14 cm
(ii) diameter is 42 cm
(iii) circumference is 264 m

Answer 1

$\underline{\underline{\bf SOLUTION :}}$

(i) Radius is 14 cm

 

Given -

radius (r) of the circle = 14 cm

To be found :

Area of the circle

 

Area of the circle = πr² unit square

[∵ In which r is the radius of the circle]

$\bf Area \:\:of\:\: the\:\: circle = \frac{22}{7}\times 14 \times 14 = 616\:\: cm^{2}$

 

________________________

 

(ii) Diameter is 42 cm

Given :

Diameter of the circle = 42 cm

radius (r) = diameter ÷ 2

radius (r) = 42 × 2 = 21 cm

Now,

To be found :

Area of the circle

 

Area of the circle = πr² unit square

[∵ In which r is the radius of the circle]

$\bf Area\:\: of\:\: the \:\:circle=\frac{22}{7}\times 21\times 21=1386\:\: cm^{2}$

 

 

________________________

 

 

(iii) Circumference is 264 m

Given

circumference of circle = 264m

To be found

Area of the circle

 

As we know that,

circumference of circle = 2πr unit

[∵ In which r is the radius of the circle]

$\bf \rightarrow 2\pi r = 264\\\\\rightarrow 2\times \frac{22}{7}\times r = 264\\\\\rightarrow r= \frac{264\times 7}{22\times 2}\\\\\rightarrow r = 42m$

Therefore,

Area of the circle = πr² unit square

[∵ In which r is the radius of the circle]

$\bf Area \:\:of \:\:the\:\: circle=\frac{22}{7} \times 42 \times 42\\\\=5544\:\: m^{2}$

Answer 2

Answer:

Step-by-step explanation:

(i) radius is 14 cm

Given :-

Radius = 14 cm.

To Find :-

Area of circle

Solution:-

Area of a circle is π(r)².

                    = 22/7 × 14 × 14  

                    = 22 × 2 × 14

                    = 44 × 14

                    = 616 cm²

(ii) Diameter is 42 cm

Given :-

Diameter = 42 cm

Radius = 42/2 = 21 cm

To Find :-

Area of circle

Solution :-

Area of a circle is π(r)².

                     = 22/7 × 21 × 21

                     = 22/7 × 441  

                     = 1386 cm²

(iii) Circumference is 264 m

Given :-

Circumference = 264 m

To Find :-

Area of circle

Solution:-

Circumference = 2πr

2πr = 264

22/7 × r = 132

r = 132 × 7/22

r = 42 cm

Area of a circle is π(r)².

                   = 22/7 × 42 × 42

                   = 5544 cm²