Angle - the space between two lines/surfaces which diverge from a common point.

Goal - the objective that you are trying to achieve.

Manipulatives - this word does not exist in a dictionary. In education, it refers to objects that can be handled and moved to help one learn. They should be common in every classroom. They are most often used during mathematics. Examples would include Cuisinaire rods, Unifix cubes and fake money.

Polya, George - He was a Hungarian mathematician, born in 1887 who is considered the Father of Problem Solving. He developed the 4 Step Problem Solving Plan and wrote the following 3 books: How to Solve It (1945), Mathematics and Plausible Reasoning (1954), and Mathematical Discovery (1962). He died in California in 1985.
The following are some great quotes from George Polya

The first rule of discovery is to have brains and good luck. The second rule of discovery is to sit tight and wait till you get a bright idea.

Mathematics is the cheapest science. Unlike physics or chemistry, it does not require any expensive equipment. All one needs for mathematics is a pencil and paper.

Look around when you have got your first mushroom or made your first discovery: they grow in clusters.

When introduced at the wrong time or place, good logic may be the worst enemy of good teaching.

Problem - a question to be answered/considered.

Relevant - necessary to the problem. Ask yourself, "Is this information needed to solve the problem?" If the answer is no then the information is not relevant (irrelevant).

Solve - to find a solution.

Square - a plane figure having four equal sides.

Strategy - a plan of action to accomplish a specific goal.

Triangle - a three-sided polygon