Answer:
Part 1) 
Part 2)
Part 3) 
Part 4) 
Step-by-step explanation:
Part 1) Find the measure of arc AB
we know that
----> by central angle
we have

therefore

Part 2) Find the measure of arc ABC
we know that
The central angle of complete circle is equal to 360 degrees
so
Part 3) Find the measure of arc BAC
we know that
----> by angle addition postulate
we have
---> by central angle
---> by central angle
so

Part 4) Find the measure of arc ACB
we know that
The central angle of complete circle is equal to 360 degrees
so

substitute

Divide the top number and the bottom number by a number they both have in common
Answer:
irrational
Step-by-step explanation:
because
5² + 6² + 2² + 50 = 25+36+4+50 = 115
and 115 is not a squared integer or rational number, so that sqrt(115) is one of these numbers with infinite digits after the decimal point but without any repeating pattern.
and that is per definition irrational.