Answer 1

In the given figure, we havex°,y° and z° forming a linear pair, therefore these must be supplementary.

That is,

 x + y +z = 180°                    (i)

Also,

`y/x = 5`

 y = 5x          (ii)

And

`z/x = 4`             

  z = 4x         (iii)

Substituting (ii) and (iii) in (i), we get:

x + 5x + 4x = 180°

            10x = 180°

               `x = (180°)/10`

                x = 18°