Question

A cone with slant height 13 cm and height 12 CM has hemispherical base find the total surface area pie is equal to 3.14

Answer 1

Hlo friend.. Cutiepie Here..

Height h of cone = 12 cm

Slant height l of cone = 13 cm

We have to find radius of cone.

Let the radius be r.

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

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

$(13)^{2} = {(r)}^{2} + (12)^{2}$

$169 = {r}^{2} + 144$

${r}^{2} = 169 - 144$

${r}^{2} = 25$

$r = \sqrt{25}$

$r = 5$

Radius r of cone = 5 cm

___________________

Total surface area of cone

$= \pi r(l + r)$

$= 3.14 \times 5 \times (13 + 5)$

$= 3.14 \times 5 \times 18$

= 282.6

Therfore,

Total surface area of cone is 282.6 cm²

HOPE IT HELPS YOU..

Answer 2

l = 13cm
h=12 cm
pie=3.14
r = ?
l^2=r^2 +h^2
r^2=l^2-h^2
r^2=(13)^2 -(12)^2
r^2=169-144
r^2=25
r=5

T.S.A OF CONE =Pie×r (l+r)
3.14×5 (13+5)
3.14×5×18
=3.14