What is radius?

Radius is the distance from the center of a circle to its edge.

Imagine you have a round pizza. The middle of that pizza is like the center, and if you draw a straight line from there all the way to the crust, that line is the radius. It's like the length of one slice’s spoon, it goes from the center of the pizza to the very tip of the crust.

Now think about a hula hoop. If you put your finger right in the middle and stretch your arm out until it reaches the edge, that's the radius too! It’s like measuring how far your arm has to reach to touch the hula hoop from its center.

A circle always has a radius, and if you know the radius, you can figure out things like the circumference, that’s the total length around the edge of the pizza or hula hoop. But for now, just remember: the radius is your go-to helper when dealing with circles!