In the case of a square or a rectangle, the expression length (1) is commonly used ... A (triangle) = 0.5 x base x height = 0.5 x b x h . ... A = 0.5 x 3 cm x 2 cm = 3 cm2 ... 2 have the same surface; the shapes of the triangles are different, but the ... Note that in a square the length and width are equal and that in a rectangle the