##### Like what you saw?

##### Create FREE Account and:

- Watch all FREE content in 21 subjects(388 videos for 23 hours)
- FREE advice on how to get better grades at school from an expert
- Attend and watch FREE live webinar on useful topics

# Central Angles and Intercepted Arcs - Problem 3

###### Brian McCall

###### Brian McCall

**Univ. of Wisconsin**

J.D. Univ. of Wisconsin Law school

Brian was a geometry teacher through the Teach for America program and started the geometry program at his school

In this problem we’re being asked to find the measure of arc X. so X is the measure of the arc between those two points. What do we know? Well we know that this chord is congruent to that chord because they have the same number of congruence marks. Well, how does that help us?

Well, to do that we’re going to take a look at what we know about congruent chords. Well they do two things, they have congruent central angles and their intercepted arcs are also congruent. So we can use that to find the measure of this arc right here which has to be congruent to 120 degrees. As I remember from the beginning of geometry, a circle is 360 degrees. So if I add up 80 degrees plus 120 degrees plus X plus 120 they need to sum to 360 degrees because that’s a full circle.

So if I add this up, 80 and 120 is 200 plus 120 is 220, excuse me 200, 320. So we find that X when we subtract 320 from both sides is going to be 40 degrees. So the measure of arc X is 40 degrees, which we found by remembering that congruent chords have congruent arcs.

Please enter your name.

Are you sure you want to delete this comment?

###### Brian McCall

B.S. in Chemical Engineering, University of Wisconsin

J.D. University of Wisconsin Law School (magna cum laude)

He doesn't beat around the bush. His straightforward teaching style is effective and his subtle midwestern accent is engaging. There's never a dull moment with him.

so my teacher can't explain this in 5 weeks but I learn this in less than 3 minutes”

its hard to focus when the teacher is really really really goodlooking”

i like how it took you 3 minutes and 8 seconds to accomplish what my teacher couldn't in 3 days”

##### Concept (1)

##### Sample Problems (4)

Need help with a problem?

Watch expert teachers solve similar problems.

## Comments (0)

Please Sign in or Sign up to add your comment.

## ·

Delete