Mathematics for IGCSE & O level - Mensuration (Section 12 - No. 19)
Which of the following shapes' area calculations involve the use of 1/2 in the formula?
Rectangle
Triangle
Parallelogram
Trapezium
Paliwanag
Triangles area is 1/2 * base * height and trapezium is 1/2 * (a+b) * h.