What theorem states that if an angle is exterior angle of a triangle then its measure is greater than the measure of either of its corresponding remote interior angles?

The exterior angle theorem
The exterior angle theorem is Proposition 1.16 in Euclid’s Elements, which states that the measure of an exterior angle of a triangle is greater than either of the measures of the remote interior angles.

What is the relationship between the measure of the exterior angle of a triangle and its remote interior angles?

What is the Exterior Angle Theorem? The exterior angle theorem states that the measure of an exterior angle is equal to the sum of the measures of the two remote interior angles of the triangle. The remote interior angles are also called opposite interior angles.

What is exterior angle Inequality Theorem?

The exterior angle inequality theorem states that the measure of any exterior angle of a triangle is greater than both of the non-adjacent interior angles.

Why is the measure of an exterior angle of a triangle equal to the sum of the remote interior angles?

Because these two adjacent angles add to 180° and the interior measures of the angles of a triangle also equal 180°, the sum of the remote interior angles ECD and CDE must equal the measure of exterior angle DEF.

Is the bisector of an angle of triangle bisects the opposite side prove that the triangle is isosceles?

Consider the ∆ABC, let AD be the bisector of ∠A and BD = CD. It is required to prove ∆ABC is an isosceles triangle i.e. AB = AC. For this draw a line from C parallel AD and extend BA. ∴ ∆ABC is an isosceles triangle.

What does an angle bisector do in a triangle?

Angle bisector. The angle bisector of an angle of a triangle is a straight line that divides the angle into two congruent angles. The three angle bisectors of the angles of a triangle meet in a single point, called the incenter .