# Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area. - Mathematics

Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.

["Assume "pi=22/7]

#### Solution

Radius (r) of the base of cone = (10.5/2)cm = 5.25 cm

Slant height (l) of cone = 10 cm

CSA of cone = πrl

=(22/7xx5.25xx10)cm^2 = (22xx0.75xx10)cm^2 = 165cm^2

Therefore, the curved surface area of the cone is 165 cm2.

Concept: Surface Area of a Right Circular Cone
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#### APPEARS IN

NCERT Class 9 Maths
Chapter 13 Surface Area and Volumes
Exercise 13.3 | Q 1 | Page 221