Download Lesson 4 Angles

Geometry 5.0 Notes—Section 1-4
Angles
__________is the union of two rays with a common endpoint.
vertex is _______
sides are _______ and _______.
Angles have three regions:
1) _______________ 2) _____________ 3) _____________
There are three ways to label an angle.
1) Three points (one point from each side and the vertex in the middle)
2) Numeral placed between the two sides.
3) Vertex (This can be used only if no other angle has the same vertex.)
Ex1)
Name all the angles._____________
There are four types of angles:
1) _______ measure < 90
3) ________ measure > 90
2) __________ measure = 90
The symbol for a right angle is
4) ___________ measure = 180
__________________ are angles with the same measure.
So if m< IJK = m< LMN, then < IJK = < LMN. (The hook marks above indicate the angles are equal.)
_______________ angles are two angles that share a vertex, a common side, and have no common interior
points.
Section 1-4 Angle Notes (continued)
Angle Addition Postulate
Ex 2
Warm Up (Day #2)
Name each of the following angles
a different way.
a) <1 _______
b) <5
c) <2 _______
d) Name a right angle________
e) <3 _______
_________
f) m< BCE = ___˚
g) <4 _______
h) < ACE appears to be a(n) __________ angle.
i)
< ABD appears to be a(n) __________ angle.
Angle Addition Postulate
If point B is in the interior of < AOC,
then m< AOB + m< BOC = m< AOC.
If < AOC is a straight angle,
then m< AOB + m< BOC = 180˚
Problems
Ex 3
Ex 5
Suppose that m< 1 = 42˚
Find m< 2.
and m< ABC = 88˚ .
Ex 4 If m< JFG = 2x and m< GFE = 5x + 5,
then find x and m< JFG.
Find the measure of each angle.
m< 1 = ____ m< 2 = _____ m< 3 = _____
m< 4 = ____ m< 5 = _____ m < 6 = _____
Ex 6 Plot each of the following points and classify the given angles as acute, right, obtuse, or straight.
A(-2,4)
i.
ACB
ii.
BCD
iii.
ACD
B(-5, 1)
C(0,0)
D(3,0)