The first side of a triangle measures 4 in. less than the second side, the third side is 3 in. more than the first side, and the perimeter is 15 in. How long is the third side?

If s represents the length of the second side, which of the following represents the length of the third side?

s - 4

s - 1

s + 3

Answer with Step-by-step explanation:

Let s represents the length of the second side of the triangle.

The first side of a triangle measures 4 in. less than the second side

i. e. length of first side = s-4

The third side is 3 in. more than the first side

i. e. length of third side = s-4+3

= s-1

The perimeter is 15 in

i. e. s-4+s+s-1=15

i. e. 3s-5=15

i. e. 3s=20

i. e. s=6.66

Length of third side = s-1

= 6.66-1

= 5.66

Hence, Length of third side = 5.66 in.

and it is represented by s-1

Lets label each side first:

r = 1st side

s = 2nd side

t = 3rd side

Now lets find the equations to each:

s - 4 = r

r + 3 = t

r+s+t = 15

It wants to know which equation would represent the third side "t". We can find the equation that solves for it; in other words the equation that has "t" isolated and that is the second equation. We can sub in the first one into it:

s - 4 = r

r + 3 = t

plug the first one into the second one by substituting the r, we should get:

(s-4) + 3=t ... s-1=t or "s - 1"