Question

if a circumference of a circle exceeds by 30 cm find the radius​

Answer 1

Answer:

Ans:7

Explanation:

Let the radius of the circle be r cm. Then, its circumference = (2πr) cm Now, (circumference) – (diameter) = 30 cm … [given] ∴ (2πr – 2r) = 30 By taking 2r common we get, = 2r (π – 1) = 30 = 2r × ((22/7) – 1) = 30 = 2r × ((22 – 7)/7) = 30 = 2r × (15/7) = 30 = (30/7) r = 30 = r = (30) × (7/30) = r = 7 cm Hence, the radius of the circle is 7 cm.Read more on Sarthaks.com - https://www.sarthaks.com/754416/the-circumference-of-a-circle-exceeds-its-diameter-by-30-cm-find-the-radius-of-the-circle

Answer 2

Answer:

Answer is 7 cm.

Explanation:

Let the radius be r cm

Then, its circumference = (2πr) cm

Now, (circumference) – (diameter) = 30 cm … given

∴ (2πr – 2r) = 30

∴ 2r because diameter = 2 x r

By taking 2r common we get,

= 2r (π – 1) = 30

= 2r × ((22/7) – 1) = 30

= 2r × ((22 – 7)/7) = 30

= 2r × (15/7) = 30

= (30/7) r = 30

= r = (30) × (7/30)

= r = 7 cm

Hence, the radius of the circle is 7 cm.