Question

The radiuss and heights of
cond wie
5cm and rem find the curved surface area
​

Answer 1

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Proper question:

The radius of base of cone is 5cm and height of cone is 12 cm. Find the curved surface area of cone.

Given:

Radius = r = 5 cm

Height = h = 12 cm

To find:

Curved surface area of cone = ?

Solution:

Curved surface area of cone = πrl

r = radius

value of π can be substituted as 22/7 or 3.14

l = slant height

Note: perpendicular to radius is height and opposite to 90° angle is slant height

slant height = √r² + h²

l = √5² + 12²

l = √ 25 + 144

l = √169

l = 13 cm

Slant height = l = 13 cm

Curved surface area of cone(CSA) = πrl

CSA = 3.14 × 5 × 13

CSA = 204.1 cm²

Or

CSA = π × 5 × 13

CSA = 65π cm²

Answer:

Therefore, Curved surface area of cone is 65π cm² or 204.1 cm²

Knowledge booster:

1. Curved surface area of cone is equal to lateral surface area
2. Total surface area of cone = πr(l+r) or Area of circular base + curved surface area of cone
3. Try to solve more such questions to get good hold on it