So you have a circle. What is the area of that circle? Surely everyone remembers that the area of a circle is: Where Pi (Ï€) is of course the number and r is the radius of the circle. Where does this ...
The radius of a circle is a line, which starts at the centre of the circle and ends on a point on the circumference. The radius is half the length of the diameter. Looking at the diagram, since OA and ...