SOLUTION: The ratio of the complements of two angles is 3:2, and the ratio of their supplements is 9:8. Find the two original angles.

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Question 1208855: The ratio of the complements of two angles is 3:2, and the ratio of their supplements is 9:8. Find the two original angles.
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52747) About Me  (Show Source):
You can put this solution on YOUR website!
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The ratio of the complements of two angles is 3:2, and the ratio of their supplements is 9:8.
Find the two original angles.
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Let the angles be x and y degrees.

Then their complements are (90-x) and (90-y) degrees.
It gives us first equation

    %2890-x%29%2F%2890-y%29 = 3%2F2.    (1)


From this equation

    2*(90-x) = 3*(90-y),

    180 - 2x = 270 - 3y

    -2x + 3y = 90.    (2)


Next, consider the supplementary angles (180-x) and (180-y)  degrees.
For them, we have this equation

    %28180-x%29%2F%28180-y%29 = 9%2F8.    (3)


It gives

    8*(180-x) = 9*(180-y),

    1440 - 8x = 1620 - 9y

    -8x + 9y = 180.    (4)


Now we have the system of to equations

    -2x + 3y = 90,     (2)

    -8x + 9y = 180.    (4)


To solve, multiply equation (2) by 4;  keep equation (4) as is 

    -8x + 12y = 360,   (2')

    -8x +  9y = 180.   (4')


Now subtract equation (4') from equation (2').  You will get

    3y = 180,

     y = 60.


To find x, substitute y= 60 into equation (2)

    -2x + 3*60 = 90  --->  180 - 90 = 2x  --->  2x = 90  --->  x = 45.


ANSWER.  The angles are  45 degrees and 60 degrees.

Solved.



Answer by greenestamps(13195) About Me  (Show Source):
You can put this solution on YOUR website!


Given that the ratio of the complements of the two angles is 3:2, let the measures of those complements be 3x and 2x.

That is a very common way to start on a problem where the ratio of two numbers is given.

The supplement of any angle is 90 degrees more than the complement. So the measures of the two supplements are 3x+90 and 2x+90.

The ratio of the supplements is 9:8.

%283x%2B90%29%2F%282x%2B90%29=9%2F8
18x%2B810=24x%2B720
6x=90
x=15

The complements of the two angles are 3x=45 degrees and 2x=30 degrees, so the two angles are 90-45=45 degrees and 90-30=60 degrees.

ANSWERS: 45 and 60 degrees