Write proofs in two-column form.
Given: . Prove: is an obtuse angle.
Angle sum property
The sum of the angles of a triangle is 180. If an angle is greater than 90 then it is an obtuse angle.
Since therefore, .
The sum of the angles of triangle will be:
Since , therefore .
From the figure
Use linear angle property as follows:
Since therefore from equation (1) .
Therefore, is an obtuse angle.
94% of StudySmarter users get better grades.Sign up for free