The first side of the triangle is 5 cm, the second is 4 cm larger than the first, and the third is 3 cm

The first side of the triangle is 5 cm, the second is 4 cm larger than the first, and the third is 3 cm smaller than the second. Find the perimeter of the triangle.

Let’s find what the length of the second side is, if it is known that it is 4 cm longer than the first, and the length of the first is 5 cm:

1) 5 + 4 = 9 (cm).

Let’s find what the third side is, if it is known that it is shorter than the second by 3 cm:

2) 9 – 3 = 6 (cm).

Let’s find what the sum of the lengths of all three sides is equal to, i.e. calculate the perimeter of the figure:

3) 5 + 9 + 6 = 20 (cm).

Answer: the sum of the lengths of all sides of the triangle is 20 cm.