SOLUTION: In a triangle, the longest side is double the shortest side and the third side is 3 cm less than the longest side. If the perimeter of the triangle is 57 cm, find all sides of the

Algebra ->  Triangles -> SOLUTION: In a triangle, the longest side is double the shortest side and the third side is 3 cm less than the longest side. If the perimeter of the triangle is 57 cm, find all sides of the       Log On


   



Question 525641: In a triangle, the longest side is double the shortest side and the third side is 3 cm less than the longest side. If the perimeter of the triangle is 57 cm, find all sides of the triangle
Found 2 solutions by Maths68, MathLover1:
Answer by Maths68(1474) About Me  (Show Source):
You can put this solution on YOUR website!
Let
Shortest side = x cm
Longest side = 2x cm
Third side = 2x-3 cm
Given
Perimeter = 57cm
Longest side + Shortest side + Third side = Perimeter of Triangle
2x+x+(2x-3)=57
3x+2x-3=57
5x=57+3
5x=60
x=60/5
x=12

Shortest side = x = 12 cm
Longest side = 2x = 12*2= 24 cm
Third side = 2x-3 cm = 24 - 3 = 21 cm

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let sides be a, b and c where c is the longest side and a is the shortest side
and the perimeter P=a%2Bb%2Bc
given:
the longest side is double the shortest side:

c=2a
and the third side is 3cm less than the longest side
b%2B3cm=c........b=c-3cm
If the perimeter of the triangle is P=57cm,than
57cm=a%2Bb%2Bc
57cm=a%2B%28c-3cm%29%2B2a...since c=2a, we have
57cm=a%2B2a-3cm%2B2a
57cm%2B3cm=5a
60cm=5a
60cm%2F5=a
highlight%2812cm=a%29....now find b and c
c=2a
c=2%2A12cm
highlight%28c=24cm%29
b=c-3cm
b=24cm-3cm
highlight%28b=21cm%29
check:
57cm=a%2Bb%2Bc
57cm=12cm%2B21cm%2B24cm
57cm=57cm