Question

the surface of two hemispheres are in the ratio 66 :121 find the ratio of radius​

Answer 1

Let two hemispheres A and B of radius r and R units. According to the Question and our assumption, The ratio of Total Surface Area of Hemisphere A to Hemispheres B is given as 66 : 121.

We know,

⇒ TSA of Hemisphere = 3πr²

So,

⇒ TSA of A / TSA of B = 66 / 121

⇒ 3πr² / 3πR² = 66 / 121

⇒ 3πr² / 3πR² = 6 / 11

⇒ r² / R² = 6 / 11

⇒ r : R = √6 : √11

So, If the ratio of total Surface area of two hemispheres is given to be 66 : 121, then the ratio of their radii will be √6 : √11

Some Formulae :-

• Volume of Hemisphere = 2/3 πr³

• Curved Surface Area of Hemisphere = 2πr²

A Hemisphere is generally half of sphere.

Answer 2

Answer:

Correct Question :

• the surface of two hemispheres are in the ratio 64 :121 find the ratio of radius

Given :

• the surface of two hemispheres are in the ratio 64 :121

Solution :

➠ 2πr1² : 2πr2² = 64 : 121

➠ r1² : r2² = 64 : 121

➠ r1² / r2² = 64 / 121

➠ r1 / r2 = √(64 / 121 )

➠ r1 / r2 = 8 / 11

➠ r1 : r2 = 8 : 11

therefore ,ratio their radius = 8 : 11