Question

The area of a circle was 49 times the area of a circle with radius 3.find the Radius of the bigger circle.

Answer 1

Given the radius of small circle = 3 cm
Area of small circle = πr²
                                 = 22/7 * 3²
                                 = 22/7 * 9
                                 = 198/7 cm²

Also given that the area of a big circle is 49 times the area of a small circle.
Let the radius of big circle = r cm
Area of big circle = πr²

Therefore
πr² = 49 (198/7)
22/7 * r² = 1386
r² = 1386 * 7/22
r² = 441
r = √441 = 21 cm

The radius of the bigger circle = 21 cm

Hope this helps you.

Answer 2

Hii friend,

Radius = 3

Therefore,

Area of circle = πr² = 22/7 × 3 × 3 = 28.28 cm².

Let the radius of big circle is R .

According to question,

Area of big circle = 49(area of small circle)

πR² = 49×28.28

πR² = 1385.72

22/7 × R² = 1385.72

R² = 1385.72×7/22

R² = 440.91

R = ✓440.91

R = 20.99 CM.

Hence,

The radius of big circle = 20.99 cm

HOPE IT WILL HELP YOU.. :-)