140 likes | 252 Views
Geometry. 1.4 Angles and Their Measure. Angles. An angle consists of two different rays that have the same initial point. The rays are the sides of the angle. The initial point is the vertex of the angle. Naming Angles. Name the angles in the figure.
E N D
Geometry 1.4 Angles and Their Measure
Angles An angleconsists of two different rays that have the same initial point. The rays are the sides of the angle. The initial point is the vertex of the angle.
Naming Angles • Name the angles in the figure
The measure of an angle can be approximated with a protractor, using units called degrees.Let’s try measuring some….
Congruent Angles Angles that have the same measure are called congruent angles.
Interior vs Exterior A point is in the interior of an angle if it is between points that lie on each side of the angle A point is in the exterior of an angle if it is not on the angle or in its interior.
Angle Addition Postulate If B is in the interior of AOC, then Thus, the measure of the bigger angle is the sum of the measure of the two smaller ones
A lawn is watered by a sprinkler that has two fixed spray heads that each spray water in a fan shape. The angle that determines each of the fan shapes is 120. The shaded area in the diagram shows where the two fan shapes overlap. Find the measure of angle 2 30 30 1 2 3
Plot the following Points • L(-5, 3) • M(-1, -1) • N(3, 3) • Q(5, -1) • P(3, -5)
Measure and classify the following angles as acute, right, obtuse, or straight • Angle LMN • Angle LMP • Angle NMQ • Angle LMQ
Two angles are adjacent angles if they share a common vertex and side, but have no common interior points