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
To solve this, we can set up an equation:
Since an equilateral triangle has all sides equal, and let's call the measure of the third side "y", we can say that:
3x + 15 = y
7x - 5 = y
Since both equations equal "y", we can set them equal to each other:
3x + 15 = 7x - 5
Simplifying the equation:
15 + 5 = 7x - 3x
20 = 4x
Dividing both sides by 4:
20/4 = x
5 = x
Now we can substitute the value of x into either of the two equations we started with:
3(5) + 15 = y
15 + 15 = y
30 = y
So the measure of the third side is 30 inches.