This question was previously asked in

DSSSB PGT Commerce Male General Section - 28 June 2021 Noon

Option 3 : 17 cm

**Given:**

The radius of the circle is 8 cm and 15 cm respectively.

**Concept:**

The area of circle = π × (The radius of the circle)^{2}

π = 22/7 or 3.14

**Calculation:**

Let be assume the radius of the big circle is R

⇒ The area of a circle whose radius is 8 cm = 22/7 × 8 × 8 = 1408/7 cm^{2}

⇒ The area of a circle whose radius is 15 cm = 22/7 × 15 × 15 = 4950/7 cm^{2}

⇒ The sum of the area of two circles = 1408/7 + 4950/7 = 6358/7

⇒ The area of big circle = π × R^{2} = (22/7) × R^{2}

⇒ According to question

⇒ (22/7) × R^{2} = 6358/7

⇒ R^{2} = 289

⇒ R = 17

**∴ The required result will be 17.**