The perimeter of a triangle is 160 cm. If two of the sides are 40 cm and 50 cm, calculate the length of the third side?
To get the perimeter, you add all the sides o the triangles, so the first two sides add up to 40+50 = <<40+50=90>>90 cm.
If the perimeter of the triangle is 160, the remaining side is 160-90 = <<160-90=70>>70 cm.
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