Question

which diagram is a net for the cube? what is the surface area of the cube? square millimeters

Explanation:

Step1: Recall cube - net property

A cube net has 6 square faces. Both given diagrams are valid nets for a cube as they can be folded to form a cube with side - length 20 mm.

Step2: Recall surface - area formula

The surface - area formula for a cube is $SA = 6s^{2}$, where $s$ is the side - length of the cube.

Step3: Substitute the side - length value

Given $s = 20$ mm, we substitute into the formula: $SA=6\times(20)^{2}$.

Step4: Calculate the result

$SA = 6\times400=2400$ square millimeters.

Answer:

2400