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Mathematics 19 Online
OpenStudy (yourboydusty):

In the diagram below, P is circumscribed about quadrilateral ABCD. What is the value of x? https://docs.google.com/document/d/1y48Rs5w4YW_IwOmc4tC7mher6cRicCPXzh5TKR71e3M/edit?usp=sharing

OpenStudy (mathstudent55):

How do I get to your doc?

OpenStudy (yourboydusty):

it should be a link if you click it...is it not working?

OpenStudy (mathstudent55):

It says I need permission.

OpenStudy (mathmate):

@YourBoyDusty You have to set the permission to "anyone with a link" or else we don't see the doc.

OpenStudy (yourboydusty):

okay try it now

OpenStudy (mathstudent55):

Ok, I'm in.

OpenStudy (mathstudent55):

You need to know this: Opposite angles of an inscribed quadrilateral are supplementary.

OpenStudy (yourboydusty):

so B would be 115 and C would be 70?

OpenStudy (mathstudent55):

You are missing two things. First, you need to deal with opposite angles. Second, they are supplementary, not congruent.

OpenStudy (mathstudent55):

Once again: In an inscribed quadrilateral, opposite angles are supplementary. 1. Can you name two pairs of opposite angles in your quadrilateral?

OpenStudy (yourboydusty):

yes < A and <c ...right?

OpenStudy (mathstudent55):

Good. A and C B and D are two pairs of opposite angles. We need A and C since one has x in it, and the other one has a measure. B and D will not help since there is no x in their measures.

OpenStudy (yourboydusty):

im sorry geometry does not like to make things easy for me...and math is hard for me...

OpenStudy (mathstudent55):

Angles A and C are supplementary. What does that mean?

OpenStudy (mathstudent55):

We're doing it one step at a time.

OpenStudy (yourboydusty):

they intersect

OpenStudy (yourboydusty):

oh...either of two angles whose sum is 180°.

OpenStudy (mathstudent55):

The second answer is correct. Two angles are supplementary angles if the sum of their measures is 180 degrees. That means that the sum of the measures of angles A and C is 180 degrees We have a measure for angle A and an expression for the measure of angle C. We add the measures and set the measure equal to 180 degrees.

OpenStudy (mathstudent55):

\(m\angle A + m \angle D = 180\) \(70 + x + 10 = 180\) Do you understand how we got the equation?

OpenStudy (yourboydusty):

i think so... Since 70+115=180 then you plug the numbers in to get an equation. Right?

OpenStudy (yourboydusty):

wait...no that equalled 185... but the sum of two angles equals 180?

OpenStudy (mathstudent55):

No. 70 + 115 = 185, but that has nothing to do with this.

OpenStudy (mathstudent55):

We are not using the 115-deg angle at all. We are only using the opposite angles A and C.

OpenStudy (mathstudent55):

Angle A measures 70 deg. Angle C measures x + 10. We know that angles and C are supplementary. That means we know that the sum of the measures of angles A and C is 180.

OpenStudy (yourboydusty):

okay i follow you...

OpenStudy (mathstudent55):

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