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

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

Answer:

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

Correct Answer: 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.