Task 1. Over each side of a given rectangle, outside of it, we construct an equilateral triangle. Calculate the perimeter of the resulting figure if the perimeter of the rectangle is 72cm.
Solution. When constructing the equilateral triangles, each side of the rectangle is replaced by two sides of the same length. According to this, the perimeter of the resulting figure is twice as large as the perimeter of the rectangle, i.e., \( L=2 \cdot 72=144 \mathrm{~cm} \).