Have You ever before Wondered...

You are watching: How many degrees are in a half circle

How numerous degrees room in a circle?What is the relationship between the radius and diameter the a circle?What execute you contact the distance approximately the leaf of a circle?

Today’s Wonder that the work was inspired by Anna grace from WInterville. Anna grace Wonders, “Why does a circle have actually infinite lines of symmetry?” many thanks for WONDERing through us, Anna Grace!


Do you prefer geometry? we do! We want to perform a Wonder that the Day about a distinct shape, but couldn"t decide which shape to feature. The more we thought about it, though, the more we kept circling ago around come the very same shape. What was it? The circle, of course!

What do you choose best around circles? We favor their perfectly round shapes. Lock don"t have actually those pointy ends you"ll uncover on squares and triangles.

Some of our favorite things are shaped prefer circles. Because that example, our favourite dessert — pie — is shaped favor a circle. And also so is our favourite toy: the hula hoop. What various other circle-shaped things execute you view or usage every day?

Geometry teachers specify a circle as the set of point out on a plane that are all the precise same distance from a central point. This way that circles are flat. Once you study circles, you find out that every circle has a radius, a diameter, a circumference, and an area.

A circle"s radius is the street from its center to that is edge. A circle"s diameter is the distance throughout the circle in ~ its widest point. The diameter of a one is always exactly twice its radius.

A circle"s perimeter — the distance all the means around its sheet — is dubbed its circumference. To calculation the circumference of a circle, you need to recognize its radius.

The formula for the one of a circle is 2πr, where r is the radius of the circle and also π is the value pi (approximately 3.141592). Due to the fact that the diameter the a one is double the radius, friend can likewise think of the formula for the one of a circle as πd, wherein d is the diameter that the circle.

The area of the circle is the measure of the variety of square systems inside that a circle. Once again, you require to recognize the radius. The formula because that the area of a one is πr2. The 2 in the formula is an exponent, which way you main point the radius by itself. So, the formula for the area of a circle could actually be written πrr instead.

One practiced thing around circles the all geometry teachers understand is that if you understand one of this facts — one of two people radius, diameter, circumference, or area — you can number out every the various other values! because that example, if you understand the radius that a circle, you can then figure out the diameter, circumference, and area.

One other interesting facet of one is that every circle have the right to be separated into 360 units called degrees. So, if you turn around in a complete circle, you revolve 360 degrees. If you merely turn halfway roughly — a half-circle — you rotate 180 degrees.

See more: What Is The Difference Between Saturated And Supersaturated Solution ?

So why 360 degrees instead of miscellaneous simpler, favor 100 degrees? Mathematicians believe the old Babylonians room to blame. In about 2400 B.C., they i found it the circular motion of the Earth about the Sun. They likewise calculated that it took about 360 days because that this circular orbit to it is in completed.

Therefore, they chose to divide the circular path right into 360 degrees. That means they might easily track each day"s i on a one calendar. So if girlfriend get puzzled in geometry by the variety of degrees in a circle, blame the Babylonians!