Calculate Cube Edge Length: Given Face Area of 9 cm²

Question

Each face of a cube has an area of 9 cm².

How long are the edges of the cube?

00:00 Find the cube's diagonal

00:03 Let's mark the cube's edge as A, all edges are equal

00:06 Each face of the cube is a square

00:09 We'll use the formula for calculating square area (side multiplied by side)

00:12 We'll substitute the area value according to the given data and solve for A

00:15 Take the square root

00:24 We'll find the two possibilities for the edge

00:28 A represents the length of an edge so it must be positive

00:33 And this is the solution to the problem

To find the edge length of the cube, we start by noting that:

Let's denote the edge length of the cube as $s$ . Since each face of the cube is a square:

$s^2 = 9$

To find $s$ , we take the square root of both sides:

$s = \sqrt{9}$

$s = 3 \text{ cm}$

Therefore, the length of each edge of the cube is $3$ cm.

$3$