Question 723040
Draw the triangle and write down what you know

Longest side: 3m
medium: m
shortest: m-4
Perimeter: 31in

write it all out in a formula solving for m (medium)

31=3m+m+m-4

That's how to put it into an algebraic equation. Stop reading from here if you want to do it yourself. After doing it once by yourself go ahead and compare and check work.


combine like terms

31=5m-4

add 4 to each side

31=5m-4
+4   +4
35=5m

divide 5 on each side

35=5m
 5  5
 7=m

now plug in to each formula

Long: 3(5)
Middle: (5)
Short: (5)-4

Answers:
Longest:15in
Medium:5in
Smallest:1in