The sum of the internal angles of a triangle is equal to 180.

∴∠A+∠B+∠C= 180

The three sectors are centered on the three vertices of the triangle and have a radius of 20cm.

In addition, there is no overlap between the three departments.

These three departments will become a semicircle with a radius of 20 cm.

The area of a semicircle is s =1/2 * π * R2 = 0.5 * 3.14 * 20 * 20 = 628 square centimeters.

The sum of the areas of the three parts is 628 square centimeters.