Question

find the radius of the cricle whose circumference is equal to the sum of the circumference of cricle with having radii15cmand8cm.

Answer 1

Let the radius of a circle be r.

∴ Circumference of a circle = 2πr

Let the radii of two circles are r and r whose values are 15 cm and 18 cm respectively.

i.e. r1 = 15 cm and r2 = 18 cm

Now, by given condition,

Circumference of circle = Circumference of first circle + Circumference of second circle

⇒ 2πr = 2πr1 + 2πr2

⇒ r = r1 + r2

⇒ r = 15 + 18

∴ r = 33 cm

Hence, required radius of a circle is 33 cm.

Answer 2

Answer:-

We have;

Let the radius of the circle be =r cm

Then, the circumference is = 2πr

According to question:-

Circum. of given circle = the sum of the circumference of cricle with having radii 15cm and 8cm.

=> 2πr = 2π(15)+2π(8)

=> Divide whole eq. by 2π

=> r = 15+8

=> r = 23cm. And