Radius of 1st Circle, r1 = 19 cm.
Circumference of 1st circle, C1 = 2πr1
Radius of 2nd circle, r2 = 9 cm.
Circumference of 2nd circle, C2 = 2πr2
Sum of the circumferences of the two circles
= 2 × 22 × 4
∴ C3 = 176 cm.
Circumference of 3rd circle, C3 = 176 cm. then, r3= ?
2πr3 = C3
∴ r3 = 28 cm