Question

a triangle has side lengths of (9.7d - 9.3) centimeters, (6.6d - 8.6) centimeters, and (4.6f - 7.7) centimeters. which expression represents the perimeter, in centimeters, of the triangle?
answer
0.4d - 3.1f - 2
-3.1f - 1.6d
16.3d + 4.6f - 25.6
-3.1f + 16.3d - 17.9

Explanation:

Step1: Sum all side lengths

$(9.7d - 9.3) + (6.6d - 8.6) + (4.6f - 7.7)$

Step2: Group like terms

$(9.7d + 6.6d) + 4.6f + (-9.3 - 8.6 - 7.7)$

Step3: Calculate like terms

$16.3d + 4.6f - 25.6$

Answer:

16.3d + 4.6f - 25.6