In a triangle, the middle length side is 3 more than the shortest side, and the longest side is double the middle length side. The perimeter of the triangle is 45 cm.

Find the lengths of the sides.

Question

In a triangle, the middle length side is 3 more than the shortest side, and the longest side is double the middle length side. The perimeter of the triangle is 45 cm.

Find the lengths of the sides.

wikiemol · Answer

you will have a triangle that looks like this:
|dw:1363752760721:dw|
its perimeter is 45 so now you have the equation x + 3x + 6x = 45

jim_thompson5910 · Answer

3 more doesn't mean 3x, it means x+3

jim_thompson5910 · Answer

let 

x = shortest side
y = middle side
z = longest side


the middle length side is 3 more than the shortest side

so 

y = x+3

the longest side is double the middle length side

which means

z = 2y

z = 2(x+3)

z = 2x + 6

------------------------------------------------

All sides must add to 45, so

x+y+z = 45

x+x+3+2x+6 = 45

I'll let you finish up

wikiemol · Answer

Right! Sorry... 
|dw:1363752969786:dw|
and x + x+3 +2(x+3) = 45

anonymous · Answer

so the middle side would be 13?

jim_thompson5910 · Answer

no

anonymous · Answer

Then what would it be?

wikiemol · Answer

I got x = 9

jim_thompson5910 · Answer

first solve for x


x+x+3+2x+6=45

4x+9=45

4x=45-9

4x=36

x=(36)/(4)

x=9

jim_thompson5910 · Answer

then use this to find y

y = x+3

y = 9+3

y = 12

y was defined to be the middle side, so the middle is 12

anonymous · Answer

i got 10. okay i see i used 49 instead of 45....

jim_thompson5910 · Answer

ah that's the culprit

anonymous · Answer

Alright, i get it now.

jim_thompson5910 · Answer

ok that's great