Find the slant height of a frustum cone whose top radius is 12 cm and bottom radius is 7 cm. The height of the cone is 12 cm.

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

15 cm

13 cm

10 cm

14 cm

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Given that,
Top radius is 12 cm.
Bottom radius is 7 cm.
Height is 12 cm.
Now,

h = 12 cm, R = 12 cm, r = 7 cm

Formula of slant height is given by,

\Rightarrow L^{2} = h^{2} + (R - r)^{2}

{\Rightarrow L}^{2} = 12^{2} + (12 - 7)^{2}

{\Rightarrow L}^{2} = 144 + 25

{\Rightarrow L}^{2} = 169

\Rightarrow L = 13 cm

Therefore, the slant height of a frustum cone

= 13 cm

.
Hence, the correct option is 2.

Watch 3-min video & get full concept clarity

JEE

NEET

Foundation JEE

Foundation NEET

CBSE