Supplementary Angles
Supplementary angles : When two angles add up to 1800
Example :
1) 60,120 2) 179, 1 3) 90,90 etc.
Important Points
i) Two acute angles can not be supplement of each other.
ii) Two right angles are always supplementary.
iii) Two obtuse angles can not be supplementary of each other.
Examples :
1) The two angles are supplementary. If one of the angle is thrice that of the other then find the two angles.
Solution :
As we know that sum of two supplementary-angles is 180
0
Let one angle be x so other angle be 3x.
x + 3x = 180
0
4x = 180
x = 180/4
x = 45
&ther4; one angle = 45
0
and other angle = 3x = 3 x 45 = 135
0
2) Two supplementary-angles differ by 34
0. Find the angles.
Solution :
Let one angle = x
0
Other angle = (x + 34)
0
As we know that sum of two supplementary-angles is 180
0
∴ x + x + 34 = 180
⇒ 2x + 34 = 180
⇒ 2x = 180 – 34
⇒ 2x = 146
⇒ x = 146/2
⇒ x = 73
Other angle = 73 + 34 = 107
0
Hence, the measures of two angles are 73
0 and 107
0
Practice
Q.1 Check whether the following angles are supplementary or not.
1) 45
0 and 130
0
2) 30
0 and 115
0
3) 112.8
0 and 67.2
0
4) 1
0 and 179
0
5) 34
0 and 150
0
Basic Geometry
• Point
• Lines
• Angles
• Lines and Angles
• Complementary angles
• Supplementary angles
• Vertically Opposite Angles
• Linear Pair Angles
• Adjacent Angles
• Parallel Lines
• Solved Problems on Intersecting Lines
• Solved Problems on Parallel Lines
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