When do we say two points are said to be collinear​

The circumference of a circle is 5 pi cm. what is the area of the circle?

Chandler was a caretaker at the state zoo. he noticed that the number of animals adopted by the zoo increased at a constant rate every year since 2010. which of the following graphs shows the slowest rate at which the animals in the zoo were adopted?

Acircle has a circumference of 28.36 units what is the diameter of the circle