SOLUTION: Two sides of a triangle are 7cm and 13cm long. The perimeter of the triangle is 30cm. Write an equation that models this problem. What is the length of the third side?

Question 997774: Two sides of a triangle are 7cm and 13cm long. The perimeter of the triangle is 30cm. Write an equation that models this problem. What is the length of the third side?
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
a+b+c= 30
a= 7
b=13
c= x
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Now, in the equation above, substitute letters for known values:
7+13+x= 30 Add numbers on the left:
20+x= 30 Subtract 20 from both sides:
x= 10 This is the length of c. Your sides are:
a= 7; b= 13; c= 10
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