Join 60,000+ competitive exam aspirants
If the heights of two cones are in the ratio 4:3 and their radii are in the ratio 3:2, what is the ratio of their volumes?
3 : 1
4 : 3
9 : 4
2 : 1
3 : 1
Express the volume ratio directly as (r2тАЛr1тАЛтАЛ)2├Ч(h2тАЛh1тАЛтАЛ) to find the result instantly.
Ratio of heights of two cones is 4 : 3 and ratio of their radii is 3 : 2
V=31тАЛ╧Аr2h
Express the volume ratio directly as (r2тАЛr1тАЛтАЛ)2├Ч(h2тАЛh1тАЛтАЛ) to find the result instantly.
Forgetting to square the radius ratio before multiplying by the height ratio.
Identify Given Data
We are given the ratio of heights h2тАЛh1тАЛтАЛ=34тАЛ and the ratio of radii r2тАЛr1тАЛтАЛ=23тАЛ.
h2тАЛh1тАЛтАЛ=34тАЛ,r2тАЛr1тАЛтАЛ=23тАЛ
Recall Cone Volume Formula
The volume of a cone is calculated using the formula V=31тАЛ╧Аr2h.
V=31тАЛ╧Аr2h
Formulate Volume Ratio
The ratio of the volumes of the two cones is V2тАЛV1тАЛтАЛ=31тАЛ╧Аr22тАЛh2тАЛ31тАЛ╧Аr12тАЛh1тАЛтАЛ=(r2тАЛr1тАЛтАЛ)2├Ч(h2тАЛh1тАЛтАЛ).
V2тАЛV1тАЛтАЛ=(23тАЛ)2├Ч34тАЛ
Calculate and Simplify
Evaluating the expression yields 49тАЛ├Ч34тАЛ=13тАЛ, which gives the volume ratio 3:1.
V2тАЛV1тАЛтАЛ=49тАЛ├Ч34тАЛ=13тАЛ
A is correct because the calculated ratio of their volumes is 3 : 1.
Similar scaling principles apply to cylinders and spheres when comparing linear dimensions to volumetric changes.