Question

A triangle has one side that measures x, and the other two sides each measure 4 inches less than x. The perimeter is 19 inches.

What is the measure of x?

Answer 1

We know that \[P=\Sigma s = s _{1}+s_{2}+s_{3}=19\]
We also know that \[s_{1}=x\] and \[s_{2}=s_{3}=x-4\]

by substitution:

\[19=x+(x-4)+(x-4)=3x-8\] so:
\[27=3x\]\[x=9\]

To check:

\[9+(9-4)+(9-4)=19\]\[19=19\] CHECK

Answer 2

so 9 right?