Answer:
D
Step-by-step explanation:
interior angles of triangle will always add up to be 180. Otherwise, trigonometry will be impossible
To complete the square, you add 
to both sides
so 
4
Answer:
Arc AB= 180 degrees
Arc BC= 15 degrees
Arc CA= 165 degrees
Step-by-step explanation:
In order to find the measure of each arc, start by recognizing that a circle equals 360 degrees, and the measure angle of the diameter of this circle is equal to half of 360 degrees, which is 180 degrees.
Since segment AB is the diameter of the circle, it will equal 180 degrees. Thus, causing arc AB equal to 180 degrees.
Next, arc BC equals 15 degrees because the measure of angle BOC is equal to the measure of arc BC.
Then, to find the measure of arc CA, use the diameter of the circle, which is segment AB. Segment AB is equal to 180 degrees, which makes arc AB equal to 180 degrees. Also known is the measure of arc BC, which is 15 degrees. To find the measure of arc CA, subtract the measure of arc BC from the measure of arc AB, and the answer will be 165 degrees.
This looks like 180 degrees - 15 degrees = 165 degrees.
To check if the arc measures are correct, add all the arc measures together. If they sum up to 360 degrees, then the measure of each arc is correct.
Answer:
I think it’s 105
Step by step explanation:
I hope this helped in some kind of way.
