a = 30°
b = 70°
c = 80°
Hi there !
a ; b ; c = angles
a + b + c = 180°
b + c = 5a
replace (b + c)
a + (b + c) = 180
a + 5a = 180
6a = 180
a = 30°
b + c = 180 - a
b + c = 150
c = b + 10
replace c
b + (b + 10) = 150
2b = 150 - 10
2b = 140
b = 70°
c = b + 10
c = 80°
Good luck !