The perimeter of an equilateral triangle is 15x+30 units. which expression can be used to show the side length of one side of the equilateral triangle? a) 15(x+2): each side length is x+2 units. b) 30(1/2x+1): each side length is 1/2x+1 units c) 5(3x+6): each side length is 3x+10 units d) 3(5x+10): each side length is 5x+10 units

Correct Option D

An equilateral triangle is the one having all sides equal in length.

Let each side of the triangle is y units in length.

So, the perimeter of triangle will be = y + y + y = 3y units

This means,

3y = 15x + 30
3y = 3 (5x + 10)
y = 5x + 10

This means, each side of the equilateral triangle is 5x + 10 units in length.
 

The first thing you should know is that an equilateral triangle is a triangle that has three equal sides.
 We then have the perimeter of the triangle:
 P = 15x + 30 units
 Its sides will be given by:
 L = P / 3
 Substituting:
 L = (15x + 30) / 3
 Simplifying:
 L = 5x + 10
 
 An expression that can be used to show the side length of one side of the equilateral triangle is
 D) 3 (5x + 10): each side length is 5x + 10 units