Atriangle has side lengths of 5a+3 5 a + 3 inches and 2a+3 2 a + 3 inches. if the perimeter of the triangle is 9a+12 9 a + 12 inches, which expression represents the lengths, in inches, of the third side of the triangle?

The answer to your question is:   side 3 = 2a + 6

Step-by-step explanation:

Data

Triangle

side 1 = 5a + 3 inches

side 2 = 2a + 3 inches

side 3 = ?

Perimeter = 9a + 12

Process

               Perimeter = side 1 + side 2 + side 3

              9a + 12 = (5a + 3) + (2a + 3) + side 3

              side 3 = 9a + 12 - 5a - 3 - 2a - 3

              side 3 = 2a + 6

1) 4 square units

2) I, II, III

3) 168 ft²