Question

a triangle has a perimeter of 56 centimeters. two of the sides measure 18 centimeters and 20 centimeters. what is the length of the third side?
centimeters
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Explanation:

Step1: Recall perimeter formula

The perimeter \( P \) of a triangle is the sum of its three sides, so \( P = a + b + c \), where \( a \), \( b \), \( c \) are the side lengths.

Step2: Substitute known values

Given \( P = 56 \), \( a = 18 \), \( b = 20 \). Let \( c \) be the third side. Then \( 56 = 18 + 20 + c \).

Step3: Solve for \( c \)

First, calculate \( 18 + 20 = 38 \). Then, \( c = 56 - 38 = 18 \).

Answer:

18