we know that
The measurement of <u>the external angle</u> is the semi-difference of the arcs it includes.
In this problem
![21\°=\frac{1}{2}[arc\ RU-arc\ SU]](https://tex.z-dn.net/?f=21%5C%C2%B0%3D%5Cfrac%7B1%7D%7B2%7D%5Barc%5C%20RU-arc%5C%20SU%5D)
Solve for the measure of arc SU
![42\°=[arc\ RU-arc\ SU]](https://tex.z-dn.net/?f=42%5C%C2%B0%3D%5Barc%5C%20RU-arc%5C%20SU%5D)


therefore
the answer is
The measure of the arc SU is 
Answer: C
Step-by-step explanation: going down would mean it's negative, so -60, and you're comparing the feet by the amount of minutes so dividing it by 2 which would be -30. so the answer would be c, -60/2=-30
1.886 to the nearest hundredth would be 2.
23 +30 (15 feet each way) = 53
28 + 30 = 58
58 x 53 = 3074ft