x+y+z+=180°
x/a = y/(a+1)=z/(a+2)=k
x=ka
z=k(a+2)
z-x=ka+2k-ka=30° ⇒ 2k=30° k =15°
x/a = y/(a+1)=z/(a+2)=15°
x=a×15°
y=(a+1)×15°=a×15°+15°
z=(a+2)×15°=a×15°+30°
x+y+z=180°
a×15°+a×15°+15°+a×15°+30°=180°
a×45°=180°-45°
a×45°=180°-45°=135°
a=3
x=a×15°=3×15°=45°
y=a×15°+15°=3×15°+15°=60°
z=a×15°+30°=3×15°+30°=75°