Recently we’ve been spending a lot of time working with circles. You may have remembered our post about how to find the
In years past, students have found the area of a rectangle by using the formula area = length x width. Now, we’ve learned how to find the area of a circle by using the formula area = πr^2. π represents the relationship between the diameter and the circumference because the circumference is about 3.14 times larger than the diameter. The letter r represents the radius of the circle. The 2 represents that you’re squaring your radius.
Jenny will walk you through the steps to finding the area of a circle by using the radius in her first ever screencast!
Our gracious mathematicians from the Math Movie Network will also share how to solve the area of pi by using the radius. They’ll also show you how to find the area if all that you’re given is the diameter of the circle!
What is the largest circle you can think of that you’ve ever seen?
The biggest cookie ever created was over 102 feet wide. What do you think the area of the cookie was?
Hello Mr. Avery and class,
Knowing how to calculate area of shapes can be very useful. Did you know for a long time people didn’t know how to calculate the area of a circle? They would estimate the area by working out the area of squares or other shapes fitted in a circle. We now have a useful formula…
area = πr^2
About 2200 years, a man named Archimedes lived in Ancient Greece. He was able to estimate the value of π but it wasn’t until the 1700s the symbol π was used.
π is a very useful symbol in maths. As well as calculating area, π is also used to calculate circumference (the distance around the outside of a circle).
circumference = 2πr
Since I was a student in school and on into teaching, I’ve always found maths interesting. I’m impressed by how skilful you all are.
Teacher, NSW, Australia
Dear Mr. Avery and class,
It is my first time on this blog and I am really impressed the way you have presented the “Area of Circle.” It’s really easy and understandable for everyone.