In triangle ABC, the length of side AB is 5 cm, side BC is 8 cm longer than side AB, and the length of side AC

In triangle ABC, the length of side AB is 5 cm, side BC is 8 cm longer than side AB, and the length of side AC is 6 cm less than the sum of the lengths of sides AB and BC, find the perimeter of the triangle.

Decision:
1) AB + 8 = BC,
5 + 8 = 13cm – BC side;
2) (AB + BC) -6 = AC,
(5 + 13) -6 = 12 cm – AC side;
3) P = AB + BC + AC,
P triangle ABC = 5 + 13 + 12 = 30 cm – ABC perimeter;
Correct answer: P = 30 cm.