The circumference of base of a right circular cone is 88 cm. If the height of the cone is 28 cm, then what is the curved surface area of the cone?

$616\sqrt{5} cm^2$

Let's first find the radius of the base of the cone.

Circumference of the base of the cone = 2\(\Pi \)r, 

⇒ 88 = 2\(\Pi \)r

⇒ r = 88/2\(\Pi \) = 14 cm,

Now, using pythagoras theorem, to find slant height

⇒ \( { l}^{2 } \) = \( { r}^{2 } \) + \( { h}^{2 } \)

⇒ \( { l}^{2 } \) = \( { 14}^{2 } \) + \( { 28}^{2 } \)

⇒ \( { l}^{2 } \) = 980

⇒ l = \(\sqrt {980 }\) = 14\(\sqrt {5 }\) cm

Now, the curved surface formula

⇒ \(\frac{22}{7}\) x 14 x 14\(\sqrt {5 }\)

⇒ 616\(\sqrt {5 }\)

Therefore, the curved surface area of cone is 616\(\sqrt {5 }\)