use models to determine the approximate formulas for the circumference and area of a circle and connect the models to the actual formulas

What is Circumference?

The circumference of a circle is the distance around that circle. But what is the formula to find the circumference? In this tutorial, you'll learn the formulas for the circumference of a circle. Take a look!
What is the Formula for the Area of a Circle?

Did you know that you can figure out the formula for the area of a circle by first turning the circle into a parallelogram? It seems a little weird, but it really works! Watch this tutorial to see how it's done!