One of the sides of the triangle is 15 cm, the length of the second is 80% of the first

One of the sides of the triangle is 15 cm, the length of the second is 80% of the first, and the length of the third is 150% of the second. What is the perimeter of this triangle?

1) Find out what is the length of the second side of the triangle. For this, we calculate 80% of the value of the first side: 15: 100 · 80 = 12 (cm);

2) Let’s calculate how many centimeters are the third side of the triangle. To do this, we find 150% of the found value of the second side of the triangle: 12: 100 · 150 = 18 (cm);

3) Knowing the magnitudes of all three sides of a given triangle, you can calculate its perimeter by the formula: P = a + b + c = 15 + 12 + 18 = 45 (cm).

Answer: the perimeter of this triangle is 45 cm.