2-7-13 Equations to find missing angles EQ: How can you write and equation to find the measure of...
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Equations to find missing angles w can you write and equation to find the mea ing angles? 1. 2. 3. 4. ing vocabulary folder and note cards to class on Fr
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Transcript of 2-7-13 Equations to find missing angles EQ: How can you write and equation to find the measure of...
2-7-13 Equations to find missing anglesEQ: How can you write and equation to find the measure of missing angles?
1.
2. 3. 4.
Bring vocabulary folder and note cards to class on Friday.
Check Homework
18013020 x X = 30
509040 x X=50
180547455 x x=-3
x+59+84+x+51=180
2x + 194 = 180
x= -7
Writing Equations to Find Missing Angles
Unit 7
Math 7
Objective-To find missing angles using rules of geometry.
Supplementary Angles- Angles whose sum is 180 .
a b
ma + m b = 180
Find the value of x.
x 30
x + 30 = 180- 30 - 30
x = 150
Find the supplement of the given angle.
1) 40
2) 18
3) 153
4) 65
5) 89
6) 23
7) 131
8) 118
140
162
27
115
91
157
49
62
Write a variable equation and solve.
Find an angle whose supplement is 30 less than twice the angle.
x 2x - 30
x + (2x - 30) = 1803x - 30 = 180
+30 +303x = 210
x = 7070
Complementary Angles - Angles whose sum is 90 .
ab
ma + m b = 90
x40
x+ 40 = 90- 40 -40
x = 50
Find the complement of...
1) 20
2) 47
3) 100
70
43
No complement
Write a variable equation and solve.
Find an angle whose complement is 20more than three times the angle.
x3x + 20
x + 3x + 20 = 90
4x + 20 = 90- 20 -204x = 704 4
x = 17.5
180 Rule for Triangles - the sum of the interiorangles of any triangle is always 180 .
a
b
c ma + m b + m c = 180
40
80
x
40 + 80 + x = 180120 + x = 180
x = 60
Find each angle below.
y+14 y - 20
2y - 10
(y + 14) + (2y - 10) + (y - 20) = 180
4y - 16 = 180+16 +16
4y = 196y = 49
y + 14 = 63
2y - 10 = 88
y - 20 = 29180
Vertical Angles Theorem - the opposite anglesof intersecting linesmust be equal.
Vertical Angles Theorem - the opposite anglesof intersecting linesmust be equal.
Find the missing angles a, b and c.
25
a
bc
25
155
155
What’s the relationship between
angles a and b?
Find the missing angle.
40 132
x
48
1804840 x18088 x
92x
Summary:How can you write and equation to find the measure of missing angles?
Homework: Vocabulary quiz on Friday; Handout; Test on Monday, 2-11-13
Bring vocabulary folder and extra cards on Friday.
