#### Question

The height of a cone is 21 cm. Find the area of the base if the slant height is 28 cm.

#### Solution

Given that

Slant height ‘l’ = 28 m.

Height of cone (h) = 21cm

∴ Radius of cone (r)=`sqrt(28^2-21^2)` [by Pythagoras theorem]

= `7sqrt(7cm)`

∴ Area of base = `pir^2`

= `22/7xx(7sqrt7)^2`

= `22/7xx7xx7=1078 cm^2`

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Solution The Height of a Cone is 21 Cm. Find the Area of the Base If the Slant Height is 28 Cm. Concept: Surface Area of a Right Circular Cone.