Question

Find the area of circle whose diameter is 42 CM.​

Answer 1

Step-by-step explanation:

Solution:

Diameter of circle = 42 cm

➜ Radius of circle = 1/2 × 42

➜ Radius of circle = 21 cm

Formula used here:

Area of circle = πr²

Putting the values:

➪ Area of circle = 22/7 × 21 × 21

➪ Area of circle = 1386 cm²

Therefore:

The area of the circle is 1386 cm².

Answer 2

Step-by-step explanation:

Given: The circumference of the circle is 42 cm.

Let the radius and diameter of the circle are r and d, respectively.

We know that,

Circumference =2πr

∴2πr=42

⇒2(

7

22

)r=42

⇒r=

22

147

≈6.68 cm

Since, the diameter of the circle is twice of it radius.

∴d=2r

⇒d=2(

22

147

)=

11

147

≈13.36

Thus, the diameter of the given circle is

11

147

cm or 13.36 (approx) cm.