Circumference: The distance around the edge of a circle. It can be calculated using the formula C = 2πr, where r is the radius.
Area of Circle: The amount of space enclosed within a circle's boundary. It can be calculated using the formula A = πr^2, where r is the radius.
Trigonometry: A branch of mathematics that deals with relationships between angles and sides in triangles, often involving trigonometric functions such as sine, cosine, and tangent.