Angle Bisector

An angle bisector is a line or ray that divides an angle into two equal parts.

Each angle formed by the bisector will measure $$\frac{\theta}{2}$$ .

The angles formed by two intersecting lines are called vertical angles, and they are equal.

Complementary angles are two angles whose measures add up to 90 degrees.

Supplementary angles are two angles whose measures add up to 180 degrees.

The sum of the measures of the angles in triangle ABC is 180 degrees.

To find the measure of an angle when given its bisector, set the two resulting angles equal to each other and solve for the variable.

Set $$3x + 5 = 2x + 30$$ and solve for $$x$$ .

$$\text{m}\text{∠GHK} = 80.5$$ because they are supplementary angles.

Set $$5x + 7 = 8x - 8$$ and solve for $$x$$ .