Circles

Finding the perimeter of semi-circles using the formula $\large~P\,=\,\frac{\pi~d}{2}\,+\,d$.

Practice using $3\frac{1}{7}$ to find area and circumference.

Practice using 3.14 to find area and circumference

Watch this video to learn why the formula for the area of a circle is π • r • r.

Finding the length of a wire that is bent into a semi-circle is just a little tricky. This lesson will help you learn how!

Learn how to find the circumference of a circle if you know the measure of the circle's diameter. $$C\,=\,\pi~\cdot~d$$