In triangle ABC, medians BD = 18cm and CE = 16.8cm. BC side length = 20cm. Find the perimeter of the BCF.

Medians BD and CE intersect with point F. By the well-known property of medians, this point divides each of them into segments in a 2: 1 ratio.

Find the length of BF:
BD / 3 = 18/3 = 6 cm;
BF = 6 * 2 = 12 cm.

Let’s find the length СF:
CE / 3 = 16.8 / 3 = 5.6 cm;
CF = 5.6 * 2 = 11.2 cm.

Let’s calculate the perimeter of triangle BCF:
P = BC + CF + BF = 20 + 12 + 11.2 = 43.2 cm.

Answer: The perimeter of the given triangle is 43.2 centimeters.