Center of a Circle

by Daisy, Jul 05 2023

What is a Circle

A circle is a round shape that looks like a ring. Imagine drawing a line with a piece of string around a centre point. This line would create a round shape with no corners or edges. A circle is a flat shape, and it's the same distance all around from the middle to the edge.

You may have seen circles in many places, like the wheels on a bicycle, a pizza, a donut, or the face of a clock. When you spin around in place, you’re also making a circle - your body is like one edge of the big round shape you're making on the ground!

Da Vinci, a famous artist, used a special tool called a compass to draw perfect circles. This tool has two points: one stays in the middle, and the other edges along the circle shape. You can try drawing a circle by tracing a round object like a cookie cutter or a glass.

The Magic Parts of a Circle

Imagine a circle as a big, round cake. There's a special point right in the middle where every part of the circle is equally close to it, like the secret treasure spot inside the cake. We call this special spot the "centre" of the circle.

Now, think about slicing your cake. When you cut a straight line from the centre to the cake's edge, you've made a "piece" called the "radius." The radius is always the same length, no matter where you cut from the centre. We usually call the radius "R" or "r."

What if you slice your cake in half? You would cut through the centre, making an even longer line that stretches across the whole cake and reaches both sides. That line is called the "diameter" of the circle, and it's twice the length of the radius.

Finally, when you cut your cake into smaller pieces, the edges of the pieces look like straight lines. Those lines are called "chords" of the circle. The longest chord we can make is the diameter.

So next time you see a circle, remember it has a special middle point, a radius, a diameter, and even chords! Circle's really are like magical cakes.

Finding the Centre of a Circle

Here is a fun activity to help you find the centre of a circle - the secret treasure spot - step-by-step:

First, draw a circle (you can draw it with your favourite colours).
Draw a straight line inside the circle. Let's call this line AB.
Now, draw another straight line in the circle below AB, which let's call that line XY.
Get your ruler, and connect points A (from the first line) with Y (from the second line), creating a diagonal line in the circle.
Then, connect points B (from the first line) with X (from the second line), making another diagonal line in the circle.
At the spot where these diagonal lines cross each other, you'll find the secret treasure spot - the centre of our circle!

Now you know how to find the magic centre point of any circle! You can practise and show your friends your special treasure-finding skills.