14. DF is 82°.
15. ∠PQR is 59°.
14. secant-secant angle CEG is equal to half the difference between the intercepted arcs' measurements, that is
∠ CEG = (DF - CG)
To eliminate the fraction, multiply both sides by 2 and apply 44° = ( 170 - DF).
88° = 170 - DF (Deduct 170 from each side.)
Multiply both sides by - 1 to get - 82 = - DF, and then
DF is 82°.
15. Half of the difference in the intercepted arcs' measurements is the tangent-tangent angle PQR.
The PSR and RP arcs were intercepted.
Since a circle's arcs add up to 360°,
360° - RP = 360° - 121° = 239° is PSR.
then
( 239 - 121)° = × 118° = 59° is the ∠PQR.