Question

If the volume of a hemisphere is 686π/3,find it's curved surface area and total surface area.(hints: curved surface area=2πr^2,total surface area=3πr^2 volume =2/3πr^3.)
Plz solve this :
And .. CSA=308cm^2,TSA=462cm^2.

Answer 1

hey mate
here's the solution

Answer 2

(i)

Given volume of hemisphere = (686π/3)

⇒ (2/3)πr^3 = (686π/3)

⇒ (2/3) * π* r^3 = 686π/3

⇒ (2/3) * r^3 = 686/3

⇒ 2r^3/3 = 686/3

⇒ 2r^3 = 686

⇒ r^3 = 686/2

⇒ r^3 = 343

⇒ r = ∛343

⇒ r = 7 m.  ------ (1)

(ii)

We know that curved surface area = 2πr^2

⇒ 2 * (22/7) * (7)^2

⇒ 2 * 22 * 7

⇒ 308 cm^2.

Therefore, Curved Surface Area = 308 cm^2.

(iii)

We know that Total surface area = 3πr^2

⇒ 3 * (22/7) * (7)^2

⇒ 3 * 22 * 7

⇒ 462 cm^2.

Therefore, Total Surface Area = 462 cm^2.

Hope it helps!