Radius vs. Diameter Always be sure you know which of these two you have and which one you need. One of the most common errors that I see is students using one in a formula when they needed the other.
Spelling A pie is something you eat. The Greek letter π is pi.
Teaching Ideas
Calculating Pi Have your students bring in different objects with circles in them, e.g. milk jar caps or tin cans. You can measure the circumference of each circle by wrapping a piece of string around it and measuring the string. If you divide the circumference by the radius of the circle, you should get π every time.
