How to determine the number of handshakes possible in a group of a certain number of people.
How to use inverse trig functions to find angles in right triangles.
How to determine the number of diagonals in a polygon.
How to define exterior angles and their remote interior angles and how to prove their properties.
How to identify a kite and its special properties.
How to derive the area formula of a kite based on the rectangle formula; how to calculate the area of a rectangle using diagonal lengths.