0.5x + 0.5 + (x - 25) + 100 + (x - 15) = 540
2.5x + 60.5 = 540
2.5x = 540 - 60.5
2.5x = 479.5
x = 479.5/2.5
x = 191.8 <===
so ur angles are :
100 <==
x - 25 = 191.8 - 25 = 166.8 <==
1/2 = 0.50 <==
1/2x = 0.5(191.8) = 95.9 <==
x - 15 = 191.8 - 15 = 176.8 <==
check..100 + 166.8 + 0.50 + 95.9 + 176.8 = 540
540 = 540 (correct)