Question

solve 3rd question....
class-9th
ch-13
ex-13.3​

Answer 1

curved suface of cone is- π rl

308=22/7*r*14

r= 308/2*22

r=7cm

total surface area=πrl+πr2

22/7*7*14+22/7*7*7

= 462

Answer 2

Given :

⬤ Curved Surface Area of Cone is 308 cm² .

⬤ Slant Height of Cone is 14 cm .

To Find :

⬤ Radius of the Base .

⬤ Total Surface Area of Cone .

Formula Used :

$\bf[\:{Curved\: Surface \: Area \: of \: Cone = \pi{r}l}\:]$

• r = Radius
• l = Slant Height

Solution :

According to the Formula :-

πrl = 308

22/7 × r × 14 = 308

44r = 308

r = 308/44

r = 7

Therefore , The Radius of the Cone is 7 cm .

Formula Used :

$\bf[\:{Total \: Surface \: Area \: of \: Cone = \pi{r}(l+r)}\:]$

• r = Radius
• l = Slant Height

Now :

• Radius = 7 cm .
• Slant Height = 14 cm .

According to the Formula :-

πr (l + r)

22/7 × 7 (14 + 6)

22 (21)

462

Therefore , The Total Surface Area of Cube is 462 cm² .