Geometry

Question Analysis:
This question tests the understanding of the side - length property of equilateral triangles.
The main focus is on the fact that all sides of an equilateral triangle are equal.

Key Concept Explanation:
By the definition of an equilateral triangle, all three sides have the same length.

Step - by - Step Solution:
Since it is an equilateral triangle and one side is 4 cm long, all sides are 4 cm long.
So the length of another side is also 4 cm.

Common Mistakes:
Forgetting the equal - side property of equilateral triangles ...