math precalculus 12

Question

The side lengths of a triangle from an Arithmetic sequence. The perimeter of the triangle is 33cm, and the longest side is 15cm. Determine the length of the other two sides.

Answer 1

The medium side is 15 - d while the shortest side is 15 - 2d. Their sum is the perimeter, so ...

15 + 15 - d + 15 - 2d = 33

45 - 3d = 33

3d = 12

d = 4 and the sides are 15, 11, and 7.