Answer:
It's a square with four equal sides each side is 6cm. The angles at the four edges are all same have 90° between each two sides. You can calculate the area of the four triangles by using the formula 1/2 × hight × base. The hight will be 6 divided by 2 which is equal 3cm, and the base will be 6cm. So the area of each triangle is 1/2×3×6=9cm^2.
