Question

What is the area (in sq cm) of a circle whose circumference is 26.4 cm?

A) 55.44 B) 44.55 C) 33.44 D) 44.33

Answer 1

C = 26.4

2πr = 26.4

r = 26.4/2π

Area = πr²

= π ( 26.4/ 2π )²

= 696.96 / 4π

= 174.24 / π

= 55.44

( A ) is the correct answer.

Answer 2

Question:

What is the area (in sq cm) of a circle whose circumference is 26.4 cm?

1. 55.44
2. 44.55
3. 33.44
4. 44.33

Answer:

1. 55.44

Given:

• Circumference of circle = 26.4 cm.

Formula Used:

1. $\tt\pink{Area \: of \: Circle = {\pi r}^{2}}$
2. $\tt\pink{Circumference \: of \: Circle = 2 \pi r}$

Solution:

★ First we need to find “r” ★

Circumference = 26.4 cm

→ 2 × π × r = 26.4

→ 2 × $= \frac{22}{7}$ × r = 26.4

→ r = 26.4 × $\frac{7}{22 \times2}$

→ r $=26.4 \times \frac{7}{44}$

→ r $= 0.6 \times 7$

→ r $= 4.2$

★ Now we can easily find the area of the circle by applying the formula of Circle ★

→ ${\pi r}^{2}$

→ $\frac{22}{7} \times 4.2 \times 4.2$

→ $\frac{22}{\cancel{7}} \times \frac{42}{10} \times \frac{\cancel{42}}{10}$

→ $22 \times \frac{42}{10} \times \frac{6}{10}$

→ $\frac{22 \times 42 \times 6}{100}$

→ $\frac{5,544}{100}$

→ ${55.44 cm}^{2}$