Groups of change with totals from 1 to 100 cents using the least amount of coins.

The arrows shows the motion direction of drawing a 30-degrees, 45-degrees, or a-60 degrees angle using…

Square with diagonal and angles labeled.

Triangles are made of various substances such as wood, rubber, celluloid, and steel.

An isosceles triangle with angles 45, 67.5, 67.5

An isosceles triangle with angles 90, 45, 45