Question

Unless stated otherwise, use t = 2.

The radii of two circles are 19 cm and 9 cm respectively.
Find the radius of the circle which has circumference equal
to the sum of the circumferences of the two circles.​

Answer 1

Answer:

Unless stated otherwise, take

1. The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles.

Ans. Let R be the radius of the circle which has circumference equal to the sum of circumferences of the two circles, then according to question,

R = 19 + 9

R = 28 cm

Answer 2

Let the radius of required circle =r cm

Radius of 1st circle r

1

=9 cm

Radius of 2nd circle r

2

=19 cm

As per the question

Circumference of the required circle = Sum of circumference of two circles

Circumference of small circle =2πr

1

=2π×9

=18π

Circumference of small circle =2πr

2

=2π×19

=38π

Now,

Circumference of the required circle = Sum of circumference of two circles

2πr=18π+38π

2πr=58π

r=

2π

56π

r=28 cm

Hence, radius of new circle is 28 cm.