Question

The measures of two of the sides of an equilateral triangle are 3x + 15 in. and 7x – 5 in. What is the measure of the third side in inches?

(1 point)
Responses

5
5

1
1

18
18

30

Answer 1

To find the measure of the third side, we can set up an equation with the two given sides. Since an equilateral triangle has all three sides equal in length, we can set the two given sides equal to each other:

3x + 15 = 7x - 5

To solve for x, we can subtract 3x from both sides:

15 = 4x - 5

Then, we add 5 to both sides:

20 = 4x

Finally, divide both sides by 4:

x = 5

Now that we have the value of x, we can substitute it back into either of the given sides to find the measure of the third side. Let's use the first given side, 3x + 15:

3(5) + 15 = 30

Therefore, the measure of the third side is 30 inches.