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Question 462566:  ∠PQR and ∠ABC are complementary angles and ∠PQR is four times as large as ∠ABC. Determine the measure of each angle. 
 Answer by math-vortex(648)      (Show Source): 
You can  put this solution on YOUR website! ∠PQR and ∠ABC are complementary angles and ∠PQR is four times as large as ∠ABC. Determine the measure of each angle. 
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A big part of solving this problem is knowing how to translate an English sentence in to algebraic language. 
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Let 
x = the measure of ∠PQR  
y = the measure of ∠ABC 
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We know that the two angles are complementary. By definition, the sum of their measures is 90 degrees. We can write this as an equation: 
[the measure of ∠PQR] + [the measure of ∠ABC] = 90 degrees 
x + y = 90 
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We also know that ∠PQR is four times as large as ∠ABC. Let's translate this into algebraic equation. 
[the measure of ∠PQR] = 4 *  [the measure of ∠ABC] 
y = 4 * x 
y = 4x 
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Now we have two equations in two variables. Let's solve for x and y. 
x + y = 90 
y = 4x 
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Substitute 4x for y in the first equation, and solve for x. 
x + y = 90 
x + (4x) = 90 
5x = 90 
x = 18 
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Substitute 18 for x in the second equation, and solve for y. 
y = 4x 
y = 4(18) 
y = 72 
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We see that the measure of ∠PQR is 18 degrees and and the measure of ∠ABC is 72 degrees.
 
18 + 72 = 90, so the two angles are complementary. 
72 = 4(18), so ∠PQR is four times as large as ∠ABC. 
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hope this helps! 
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Ms.Figgy 
math.in.the.vortex 
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