I have included two worksheets that my students used to find the area of irregular shapes. It is set up so that students can break the shapes into squares, rectangles or triangles. This should be used after students have learned the area equations for those shapes. It is also a good review for decimal multiplication.
6.G.1- Students decompose shapes into rectangles and triangles to determine the area. For example, a trapezoid can be decomposed into triangles and rectangles (see figures below). Using the trapezoid’s dimensions, the area of the individual triangle(s) and rectangle can be found and then added together. Special quadrilaterals include rectangles, squares, parallelograms, trapezoids, rhombi, and kites.