yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Measuring angles with a circular protractor | Math | 4th grade | Khan Academy


less than 1m read
·Nov 11, 2024

Measure the angle in degrees. So here we have this blue angle that we want to measure in degrees, and it's sitting on top of this circle. That circle is actually a protractor. Sometimes we see, and maybe what you're used to seeing, is protractors that are more semicircle shaped, something like this.

Those semicircle protractors measure from 0 to 180°, which is good, but a circle is even better. A full circle is better because an angle can measure up to 360°. So, a full circle allows us to measure an angle of any size instead of only an angle up to 180°. Now, the way we're going to measure this angle is the same way we would on a semicircle protractor.

The first thing we want to do is make sure one of our rays lines up to zero. So here's one of our rays, and it's lining up to zero on the protractor. So that's nice; it's already lined up for us. Then we're going to measure the opening all the way to the other ray, to right here.

So, if our angle only measured and opened up this far, it would be a 10° angle. If, let's say, it opened here, it would be a 50° angle. But our angle measures all the way to here, to the 160°. So, 160° is the measure of our angle. And again, when you measure on a circle protractor or any protractor for that matter, you're going to line one ray up to the zero and then measure the opening till you get to the other ray, which in this case opened up to 160°.

More Articles

View All
Counting by tens | Counting | Early Math | Khan Academy
So we are told, let’s count by tens, and we go 10, 20, blank, 40, 50, 60, 70, 80, 90, 000. What number did we miss? Pause the video. What number did we miss right over here? Well, if we’re counting by tens, we would go 10, 20, 30, 40, 50, 60, 70, 80, 90, …
Khan Academy Ed Talks with Barbara Oakley, Phd - Thursday, June 15
Hello and welcome to Ed Talks with Khan Academy, where we talk to influential people in the education space about learning and teaching. Today, we are pleased to welcome Dr. Barbara Oakley, who is celebrating the launch of her new book, Uncommon Sense Tea…
15 Things Broke People Always Have Money For
You personally know that they don’t have any money yet. They’re still spending like they didn’t just ignore that third eviction notice. From a financial perspective, some people are just built different, but not in a good way. They spend their money on du…
The History of the Bible, Animated | National Geographic
Along the shores of the Dead Sea, three Bedouin shepherds were tending their flocks when one of their goats strayed from the herd. Thinking it had wandered into a cave, one of them threw a stone to scare the animal out. The unexpected sound sparked their …
Ideology and social policy | US government and civics | Khan Academy
In this off-white color, I have a handful of statements that you might hear folks say, especially in the United States. What we’re going to think about is, are these statements that you would typically hear from a liberal? I’m gonna make a little key here…
How to sell private jets to billionaires
Excuse me, what do you do for a living? I sell jets. Wait, are you Steve Bano? It depends who’s asking. Oh my God, Steve, can you show me around the showroom? Yeah, sure, come on in. Steve, I love this sign! You love this thing? Time is money, buy a je…