Final answer:
Assuming the triangle is equilateral, each side would be the total perimeter (126 units) divided by the number of sides (3 sides), resulting in each side being 42 units long.
Step-by-step explanation:
To find the measure of each side of a triangle when given the perimeter, you'll usually need more information about the triangle, as different triangles could have the same perimeter but different side lengths. However, if we assume the triangle is equilateral (which is not stated in the question but is the only case where we can determine the side lengths without additional information), we can divide the perimeter by the number of sides, which is 3 for a triangle.
An equilateral triangle has all three sides of equal length. If the perimeter is 126 units, each side would be the total perimeter divided by 3.
Side length = Perimeter / Number of sides
Side length = 126 units / 3
Side length = 42 units
Each side of an equilateral triangle would be 42 units long.