You get two congruent right triangles when you divide a rectangle diagonally.

(This is one way to show that the area of each of those triangles is 1/2*base*height. Rectangle area = (4 in)(8 in) = 32 in

(This is one way to show that the area of each of those triangles is 1/2*base*height. Rectangle area = (4 in)(8 in) = 32 in

^{2}. Triangle area = (1/2)(4 in)(8 in) = 16 in^{2}.)