Area by Radial Survey PowerPoint

This PowerPoint explains the practical method of measuring land by radial survey.
The area formula ½bh → ½abSinC
Then an example of 4 triangles used to find the area of an non-regular quadrilateral.
Next a quadrilateral that is intended to be worked as a class, before revealing the solution.
Then one pentagonal and one hexagonal piece of land that students can calculate areas for either from the display or on a worksheet (also included) again before revealing the solution.
My students have responded more enthusiastically to this presentation than standard text work.