1-3 Measuring Angles Geometry

Angles can also be named by a #. (____) Angle symbol: 2 rays that share the same endpoint (or ________ ________) Sides – the rays XY & XZ Vertex – the common endpoint; X Y X 5 Z Named _______, ______ (vertex is always in the middle), or ___ (if it’s the only ___ in the diagram). Angles can also be named by a #. (____)

There are 3 different <B’s in this diagram; therefore, none of them should be called <B.

Angle Measurement m<A means the “measure of <A” Measure angles with a _____________. Units of angle measurement are _________ (o). Angles with the _____measure are congruent angles. If m<A = m<B, then <A <B.

Postulate 1-3-1: Protractor Post. The rays of an angle can be matched up with real #s (from 1 to ___) on a protractor so that the measure of the < equals the absolute value of the ____________of the 2 #s. 55o 20o m<A = __- __ = ___o

Interior or Exterior? B is ___________ C is ___________ D is ___________ in the in the on the B C D A

Post. 1-3-2: Angle Addition post. If P is in the interior of <QRS, then m<QRP + m<PRS = m<QRS. If m<QRP=5xo, m<PRS=2xo, & m<QRS=84o, find x _____________ m<QRP __________ & m<PRS. ___________ S P Q R

Types of Angles Acute angle – Right angle – Obtuse angle – Straight angle – Measures _________ 0o & 90o Measures __________ 90o Measures _________ 90o & 180o Measures ____________ 180o

Adjacent Angles 2 angles that share a __________ vertex & side, but have ____ common interior parts. (They have the same vertex, but don’t overlap) such as <1 & <2.) 2 1

Example 1: Name an acute angle Name an obtuse angle Name a right angle Name a straight angle S T 3 1 2 A B C

Assignment