Answer:
a)
The angle formed by intersecting chords is half of the sum of the intercepted arcs:
- 1/2(mST + mPR) = m∠PUR
- 1.2(74° + mPR) = 77°
- 74° + mPR = 2*77°
- mPR = 154° - 74°
- mPR = 80°
b)
The angle formed by two tangents is the half of the difference of the intercepted arcs:
- m∠PSR = 1/2(mPTR - mPR)
- m∠PSR = 1/2(247° - (360° - 247°))
- m∠PSR = 247° - 180°
- m∠PSR = 67°
