The sum of the circumference and diameter of a circle is 116 cm. Find its radius.

Given:

Circumference of a circle + Diameter of a circle = 116 cm

$⇒ 2πr + 2r = 116\\[1em] ⇒ 2r(π + 1) = 116\\[1em] ⇒ 2r\Big(\dfrac{22}{7} + 1\Big) = 116\\[1em] ⇒ 2r\Big(\dfrac{22 + 7}{7}\Big) = 116\\[1em] ⇒ 2r\Big(\dfrac{29}{7}\Big) = 116\\[1em] ⇒ r\Big(\dfrac{58}{7}\Big) = 116\\[1em] ⇒ r = \dfrac{116 \times 7}{58}\\[1em] ⇒ r = \dfrac{812}{58}\\[1em] ⇒ r = 14 \text{ cm}$

Hence, the radius of a circle is 14 cm.