1.

If radius of a cone is increased by 30% and height increased by 20%, then what is the ratio of new volume to initial volume?1. 250 : 50.72. 50.7 : 2503. 507 : 2504. 250 : 5075. None of these

Answer» Correct Answer - Option 3 : 507 : 250

Given:

Increase in radius of cone = 30%

Increased in height of cone = 20%

Formula used:

V = (1/3) × π × r2 × h

where,

V = volume of cone

r = radius of cone

h = height of cone

Calculations:

Let the initial radius and height of the cone be r, h.

Initial volume = (1/3) × π × r2 × h

New radius = r + (r × 30%)

⇒ 13r/10

New height =  h + (h × 20%)

⇒ 6h/5

New volume = (1/3) × π × (13r/10)2 × (6h/5)

⇒ (1/3) × π × (169r2/100) × (6h/5)

⇒ (1/3) × π × r2 × h × (169/100) × (6/5)

⇒ (Initial volume) × (169/100) × (6/5)

(New volume)/(Initial volume) = 507/250

∴ The ratio of new volume to initial volume is 507 : 250.



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