Geometry

Things to remember:
1) Angles on a straight line add up to 180 degrees.
2) Angles at a point add up to 360 degrees.
3) Base angles of isosceles triangles are equal.
4) All angles of an equilateral triangle are 60 degrees.
5) In a parallelogram and rhombus, opposite angles are equal.
6) Angles within 2 parallel lines add up to 180 degrees.
7) Alternate angles are equal.
8) Corresponding angles are equal.
9) The diagonal of a rhombus divides the rhombus into 2 isosceles triangles.