We will ave the following:
*First: We will determine the sum of all internal angles of the polygon:
[tex](n-2)\cdot180\Rightarrow(5-2)\cdot180=3\cdot180[/tex][tex]=540[/tex]
*Second: Now, that we know that the sum of all internal angles will be 540°, the following is true:
[tex]90+90+135+135+\alpha=540[/tex]
Now, we solve for alpha [The angle]:
[tex]\Rightarrow\alpha=540-135-135-90-90\Rightarrow\alpha=90[/tex]
So, the measure of the angle at the bottom is 90°.
