Question

Solve the following, 29th

Answer 1

Hlo friend.. Cutiepie Here..

Here is ur answer :

Height h of cone = 15 cm

Radius r of cone = 8 cm

First, we have to find Slant height

Let the Slant height be l

${(slant \: \: height)}^{2} = {(height)}^{2} + {(radius)}^{2}$

${l}^{2} = {h}^{2} + {r}^{2}$

${l}^{2} = {(15)}^{2} + {(8)}^{2}$

${l}^{2} = 225 + 64$

${l}^{2} = 289$


$l = \sqrt{289}$


$l = 17 \: \: cm$


____________________

Curved surface area of cone

$= \pi rl$

$= \pi \times 8 \times 17$


$= \pi \times 136$


$= 136\pi \: {cm}^{2}$


Therfore, option (d) is correct.


HOPE IT HELPS YOU..

Answer 2

Hey mate...
========

Height of a cone , h = 15 cm

Base radius of a cone , r = 8 cm

Slant Height of a cone , L = ?

Curved Surface area of a cone = ?

We know,

L^2 = r^2 + h^2

= (15)^2 + (8)^2

= 225 + 64

= 289

Thus,

L = 17 cm

We know,

Curved Surface area of a cone = πrL

= π × 8 × 17

= 136π cm^2