The two supplementary angles are 109° and 71°.
Understanding Supplementary Angles
Supplementary angles are a fundamental concept in geometry that describes a special relationship between two angles. By definition, two angles are considered supplementary if the sum of their individual measures is exactly 180°. This concept is often visualized as two angles that, when placed adjacent to each other, form a straight line. For example, if we have two angles, let's call them Angle A and Angle B, they are supplementary if their measures satisfy the equation:
Angle A+Angle B=180∘Angle A plus Angle B equals 180 raised to the composed with power
AngleA+AngleB=180∘
It's important to distinguish supplementary angles from complementary angles, which are two angles that add up to 90°.
The Problem: Finding the Angles
The problem states that we have two supplementary angles, and the difference in their measures is 38°. To solve this, we can use a system of linear equations, which is a powerful algebraic method for solving problems with multiple unknown variables.
Setting Up the Equations
First, let's represent the two unknown angle measures with variables. We can use xx
𝑥
and yy
𝑦
to represent the measure of each angle. Based on the problem's information, we can create two equations:
-
Supplementary Angle Equation: Since the angles are supplementary, their sum is 180°.x+y=180x plus y equals 180
𝑥+𝑦=180
-
Difference Equation: The difference between the two angles is 38°. To ensure a positive difference, we can assume xx
𝑥
is the larger angle.x−y=38x minus y equals 38
𝑥−𝑦=38
Solving the System of Equations
Now, we have a system of two equations with two variables. A straightforward way to solve this is using the elimination method. By adding the two equations together, we can eliminate one of the variables.
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Add the two equations: We'll add the left side of both equations and the right side of both equations.(x+y)+(x−y)=180+38open paren x plus y close paren plus open paren x minus y close paren equals 180 plus 38
(𝑥+𝑦)+(𝑥−𝑦)=180+38
-
Simplify the equation: The +ypositive y
+𝑦
and −ynegative y
−𝑦
terms cancel each other out, leaving us with a single variable, xx
𝑥
.2x=2182 x equals 218
2𝑥=218
-
Solve for x: To find the value of xx
𝑥
, we divide both sides by 2.x=2182x equals 218 over 2 end-fraction
𝑥=2182
x=109x equals 109
𝑥=109
We have now found the measure of the first angle, which is 109°.
Finding the Second Angle
With the value of xx
𝑥
known, we can substitute it back into either of our original equations to find the value of yy
𝑦
. Using the first equation is often the simplest approach:
-
**Substitute x into the first equation:**109+y=180109 plus y equals 180
109+𝑦=180
-
Solve for y: To isolate yy
𝑦
, we subtract 109 from both sides of the equation.y=180−109y equals 180 minus 109
𝑦=180−109
y=71y equals 71
𝑦=71
The measure of the second angle is 71°.
Verification and Final Answer
Finally, it's good practice to verify our answers by checking if they satisfy the initial conditions of the problem.
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**Are they supplementary?**109∘+71∘=180∘109 raised to the composed with power plus 71 raised to the composed with power equals 180 raised to the composed with power
109∘+71∘=180∘
Yes, they are supplementary.
-
**Is their difference 38°?**109∘−71∘=38∘109 raised to the composed with power minus 71 raised to the composed with power equals 38 raised to the composed with power
109∘−71∘=38∘
Yes, their difference is 38°.
Both conditions are met, confirming that our calculations are correct. The two angles are 109° and 71°.
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