How do you estimate the area under a curve using triangles and trapeziums?

You estimate the area under a curve using triangles and trapeziums, by splitting the graph vertically so that each value X becomes a trapezium or triangle, and then calculating the area of the shapes with their given coordinates, e.g. as the area of a triangle is ½ x base x height, if the triangle’s base is 1, and its height is 4.4, the equation becomes ½ x 1 x 4.4 = 2.2, which is added to the other shapes areas