Two cubes have sides of length 3 cm and 8 cm. what is the ratio of their respective surface areas?

1) For cube with a side = 3 cm.

Area of one face = 3², surface area for this cube = 6*3².

2) For cube with a side = 8 cm.

Area of one face = 8², surface area for this cube = 6*8².

3) Ratio of their surface areas = surface area with side3/surface area with side8 =

= 6*3²/6*8²=3²/8² = 9/64

Answer is 9/64.

The surface area formula for a cube is: 6 * s^2, where s is the side length.

The two surface areas are:

6 * 3^2 = 54

and

6 * 8^2 = 384

The ratio of their surface areas, from the surface area of the smaller cube to the surface area of the larger cube is:

54/384 = 9/64

The answer is 9/64.

Note that another way to to find the ratio of the squares of the side lengths of the cubes.