How to find the length of an edge of a cube - GRE Quantitative Reasoning

Card 1 of 24

0
Didn't Know
Knew It
0
1 of 2019 left
Question

Quantity A: The length of a side of a cube with a volume of .

Quantity B: The length of a side of a cube with surface area of .

Which of the following is true?

Tap to reveal answer

Answer

Recall that the equation for the volume of a cube is:

Since the sides of a cube are merely squares, the surface area equation is just times the area of one of those squares:

So, for our two quantities:

Quantity A

Use your calculator to estimate this value (since you will not have a square root key). This is .

Quantity B

First divide by :

Therefore,

Therefore, the two quantities are equal.

← Didn't Know|Knew It →