In the given diagram, there are two exterior angles, each of measurement 2h degree.
So to find the adjacent interior angles, we have to use linear pair, that is sum of exterior and adjacent angle to exterior angles are supplementary.
Let the adjacent interior angle be y degree.
[tex]2h + y =180
\\
y = 180-2h[/tex]
So the each base angle of the triangle is of measurement
[tex](180-2h)degree[/tex]
And sum of measurement of angles of a triangle is 180 degree.
[tex]40+ 180-2h+180-2h =180
\\
400 -4h = 180
\\
4h = 220
\\
h= 55 degree[/tex]
