Question

determine all marked angles in the following figure in which L || m.​

Answer 1

Angle a=50
Angle b=70

Answer 2

$let \: that \: angle \: be \: x \\ \\ so \: angle \: 60 \: = x \\ (alternate \: interior \: angles) \\ \\ so \: angle \: x \: is \: 60\\ \\ if \: x \: = \: 60 \\ \\ then \: b + x + 50 = 180 \\ (linear \: pair) \\ \\ 60 + x + 50 = 180 \\ x = 180 - 110 \\ x = 70 \\ \\ if \: angle \: b \: is \: 70 \\ \\ 60 + 70 + a = 180 \\ (all \: angles \: of \: trianle \: = 180) \\ a = 50$