Respuesta :

Step-by-step explanation:

1) the rule: m∠1+m∠2+m∠3=180°;

2) according to the rule above: m∠P+m∠Q+m∠R=180°;

x+x+43+2x-15=180°; ⇔ 4x=152°; ⇒ x=38°;

3) the angles: P=2x-15=61°; Q=x+43=81°; R=x=38°.