Question

The formula s = StartRoot StartFraction S A Over 6 EndFraction EndRoot gives the length of the side, s, of a cube with a surface area, SA. How much longer is the side of a cube with a surface area of 1,200 square inches than a cube with the surface area of 768 square inches?

Answer 1

Answer:

$2\sqrt{2}\ ft\ longer$

Step-by-step explanation:

Area Of A Cube

Suppose a cube with side length s, the area of one side is

$A_s=s^2$

Since the cube has 6 sides, the total area is

$A=6A_s=6s^2$

But if we have the area, we can solve the above formula for s to get

$A=6s^2$

$\displaystyle s=\sqrt{\frac{A}{6}}$

We have two different cubes with areas 1,200 square inches and  768 square inches. Let's compute their side lengths

$\displaystyle s_1=\sqrt{\frac{1,200}{6}}=\sqrt{200}$

$\displaystyle s_1=10\sqrt{2}\ ft$

$\displaystyle s_2=\sqrt{\frac{768}{6}}=\sqrt{128}$

$\displaystyle s_2=8\sqrt{2} ft$

The difference between them is

$10\sqrt{2}\ ft-8\sqrt{2}\ ft=2\sqrt{2}\ ft\approx 2.83\ ft$

The side of the cube with area 1,200 square inches is $2\sqrt{2}\ ft$ longer then the side of the cube with area 768 square inches

Answer 2

Answer:

B) 2√2 on edge