Problema Solution
An isosceles triangle has two sides of equal length. The third side is 5 less than twice the length of one of the other sides. If the perimeter of the triangle is 23 cm, what is the length of the third side?
Answer provided by our tutors
let
a = the length of the same sides
b = the length of the third side
the third side is 5 less than twice the length of one of the other sides.
b = 2a - 5
the perimeter of the triangle is 23 cm and since the perimeter P = 2a + b we have
2a + b = 23
by solving the system of equations
b = 2a - 5
2a + b = 23
we find
a = 7 cm
b = 9 cm
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the length of the third side is 9 cm.