Geometry

[talaangoshtari]

A sector of a circle of radius 5 cm is recast into a right circular cone of height 4 cm. What is the volume of the resulting cone?

A. 12Ï€ cm3
B. 100Ï€ cm3
C. 33Ï€ cm3
D. 32Ï€ cm3
E. 4Ï€ cm3

[Jim@StratusPrep]

This is essentially saying that you are to calculate the volume of a cone with a radius of 5 and height 4.

1/3Ï€r^2h = = 1/3(100Ï€) = 33Ï€

However, not likely a phrasing you will see on the GMAT.

[Brent@GMATPrepNow]

A sector of a circle of radius 5 cm is recast into a right circular cone of height 4 cm. What is the volume of the resulting cone?

A. 12Ï€ cm3
B. 100Ï€ cm3
C. 33Ï€ cm3
D. 32Ï€ cm3
E. 4Ï€ cm3

On the GMAT, you don't need to know the formula for the volume of a cone.

Cheers,
Brent

[[email protected]]

Hi talaangoshtari,

When it comes to geometric 'solids', you DO need to know the formulas for Volume and Surface area for rectangular solids, cubes (which are just a specific type of rectangular solid) and cylinders. You do NOT need to memorize anything involving spheres, cones or pyramids. In the rare situation in which you deal with one of those shapes, you'll be given the necessary formula(s) to work with.

GMAT assassins aren't born, they're made,
Rich

[nikhilgmat31]

what recast means here.
Does it means volume of sector of sphere is casted to make a cone.

or I am think too much.