Question

in the adjoining figure,find the value of a

Answer 1

3y+y=180(Angles on a st. line)

4y=180

y=45°


a=y(Vertically opposite angles)

∴a=45°

Answer 2

in given figure 3y+y=180 degree 
it means y=180/4=45degree 
y+3y+3y+a=360 degree
7*45+a =360
315+a=360
⇒ a=45°