I think is the same formula area .A triangle is half as big as the rectangle that surrounds it, which is why the area of a triangle is one-half base times height.
Step-by-step explanation:
The area of a rectangle is given by the relation length* width. The area of a triangle is given by the relation (1/2)*base* height. Now we know that the two have the same area equal to 150 cm^2. Also, when placed on the same level the tip of the triangle touches the upper edge of the rectangle.