Given:
The three exterior angles of a pentagon measures 60,80 and 90.
To find:
The measure of other two exterior angle, assuming them equally.
Solution:
Let x be the measure of two other exterior angles of the pentagon.
We know that the sum of all exterior angles of a pentagon is 360 degrees.
[tex]60^\circ+80^\circ+90^\circ+x+x=360^\circ[/tex]
[tex]230^\circ+2x=360^\circ[/tex]
[tex]2x=360^\circ-230^\circ[/tex]
[tex]2x=130^\circ[/tex]
Divide both sides by 2.
[tex]\dfrac{2x}{2}=\dfrac{130^\circ}{2}[/tex]
[tex]x=65^\circ[/tex]
Therefore, the measures of both exterior angles are 65 degrees.
