Please teach me how to find the measurements in this circle?

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endoplasmicreticulum

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Please teach me how to find the measurements in the circle. I know the circle theorems but am still confused on what to do.
 

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endoplasmicreticulum said:
Is arc AD 200? since the inscribed angle is half the arc?
Click to expand...
No. The marked 100 degree angle AOD is not an inscribed angle, but a central angle; so arc AD has measure 100 degrees.

I would mark the other three central angles (at O) and use those to find the arcs in the same way.

Then I would find the inscribed angles, such as DAC.

Then angle AED is different; you might think about quadrilateral AEDO. What are the angles at A and D? Or you might have a theorem you can apply directly.
 
Dr.Peterson said:
No. The marked 100 degree angle AOD is not an inscribed angle, but a central angle; so arc AD has measure 100 degrees.

I would mark the other three central angles (at O) and use those to find the arcs in the same way.

Then I would find the inscribed angles, such as DAC.

Then angle AED is different; you might think about quadrilateral AEDO. What are the angles at A and D? Or you might have a theorem you can apply directly.
Click to expand...

the arc will have the same measure as a central angle? does that mean all the angles in the center have the same measurement as arcs?

I think
angle BOC will be 100,
angle AOB will be 80
angle DOC will be 80?
does it make the arcs across from it the same?

The inscribed angle DAC will be 40 since arc DC is 80.

quadrilateral had to equal 360,
and angle A and D are congruent
angle A and D are 40?
40+40+100+180 = 360
angle AED = 180?


arc AD = 100
arc DC = 80
arc AB = 80
angle DAC = 40
arc ACD = 260
angle ACB = 40
angle AED = 180
arc ADC = 180
 
endoplasmicreticulum said:
the arc will have the same measure as a central angle? does that mean all the angles in the center have the same measurement as arcs?
Click to expand...
Yes.

endoplasmicreticulum said:
angle BOC will be 100,
angle AOB will be 80
angle DOC will be 80?
does it make the arcs across from it the same?
Click to expand...
Yes.

endoplasmicreticulum said:
The inscribed angle DAC will be 40 since arc DC is 80.
Click to expand...
Yes.

endoplasmicreticulum said:
quadrilateral had to equal 360,
and angle A and D are congruent
angle A and D are 40?
40+40+100+180 = 360
angle AED = 180?
Click to expand...
Does it look like 180?? Can EAO and EAO possibly be 40 degrees?

What is true of an tangent and the radius?

endoplasmicreticulum said:
arc AD = 100
arc DC = 80
arc AB = 80
angle DAC = 40
arc ACD = 260
angle ACB = 40
angle AED = 180
arc ADC = 180
Click to expand...
Just fix AED.
 
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