Answer:
In geometry, the area enclosed by a circle of radius r is πr2. Here the Greek letter π represents a constant, approximately equal to 3.14159, which is equal to the ratio of the circumference of any circle to its diameter.
Explanation:
Answer:
I say when u don't know the answer completly.
Rapid prototyping as it allows the production of a functional program in a short time
Insert Control, I believe.