Final answer:
The minimum length of the shortest side of the triangle is 9 cm.
Step-by-step explanation:
To find the minimum length of the shortest side of the triangle, we need to set up equations based on the given information. Let's say the shortest side is x cm. According to the problem, the longest side is 3 times the shortest side, so the longest side is 3x cm. And the third side is 2 cm shorter than the longest side, so it is (3x - 2) cm. The perimeter of the triangle is at least 61 cm, which can be expressed as:
x + 3x + (3x - 2) ≥ 61
Simplifying this equation, we get:
7x - 2 ≥ 61
Adding 2 to both sides, we get:
7x ≥ 63
Dividing both sides by 7, we get:
x ≥ 9
Therefore, the minimum length of the shortest side is 9 cm.