If the sum of two sides of an equilateral triangle is 16 cm, then find the third side.

The correct option is 8 cm.

Let us break down the solution step-by-step:

1. Understand the definition of an equilateral triangle:
An equilateral triangle is a triangle in which all three sides are equal in length.
If we let $s$ represent the length of one side of the equilateral triangle, then all three sides of the triangle have a length equal to $s$.

2. Use the given information to set up an equation:
We are given that the sum of two sides of this equilateral triangle is 16 cm.
Since any two sides each have length $s$, their sum is:

$s+s=16$

3. Solve for the side length $s$:

$2s=16$

Divide both sides of the equation by 2:

$s=\frac{16}{2}$

$s=8\text{cm}$

4. Find the third side:
Since all three sides of an equilateral triangle are equal, the length of the third side is also $s$, which is 8 cm.