Answer:
The third exterior angle is [tex]103^o[/tex]
Step-by-step explanation:
Given
[tex]\theta = 158^o[/tex]
[tex]\alpha = 99^o[/tex]
Required
The third exterior angle [tex](\beta)[/tex]
The exterior angles of a triangle add up to 360 degrees.
So:
[tex]\theta + \alpha + \beta = 360^o[/tex]
Make [tex]\beta[/tex] the subject
[tex]\beta = 360^o - (\theta + \alpha)[/tex]
Substitute known values
[tex]\beta = 360^o - (158^o + 99^o)[/tex]
[tex]\beta = 103^o[/tex]
