Practicing Success
In ΔPQR ∠Q = 66° and ∠R = 34°. T is a point on QR. and S is a point between Q and T such that PS ⊥ QR and PT is the bisector of ∠QPR. What is the measure of ∠SPT? |
20° 16° 18° 12° |
16° |
\(\angle\)QPR = \({180}^\circ\) - \({66}^\circ\) - \({34}^\circ\) ⇒ \({80}^\circ\) \(\angle\)QPT = \(\angle\)TPR = \({40}^\circ\) [As PT angle bisector] In \(\Delta \)PTR \(\angle\)PTR + \(\angle\)PRT + \(\angle\)TPR = \({180}^\circ\) ⇒ \(\angle\)PTR = \({180}^\circ\) - \({34}^\circ\) - \({40}^\circ\) ⇒ \(\angle\)PTR = \({106}^\circ\) Now, \(\angle\)PTS + \(\angle\)PRT = \({180}^\circ\) ⇒ \(\angle\)PTS + \({106}^\circ\) = \({180}^\circ\) ⇒ \(\angle\)PTS = \({180}^\circ\) - \({106}^\circ\) ⇒ \(\angle\)PTS = \({74}^\circ\) So, \(\angle\)STP = \({180}^\circ\) - \({90}^\circ\) - \({74}^\circ\) ⇒ \(\angle\)SPT = \({16}^\circ\) Therefore, \(\angle\)SPT is \({16}^\circ\). |