Thread: Complement and Supplement of an angle

Find the measure of angle A if 5 times the complement of angle A is 150 greater than the supplement of angle A.

I have this
Let s be supplement and c be complement.
180-A = s
90-A= c


5c-150= s
I plugged the above in.

5c-150=180-A
Then plugged in my definition for c.
5(90-A) - 150 = 180 - A
450-5A + A=180 + 150
-4A=330-450
-4A=-120
A= 30.

Huh. That's strange I got it right this time.
ANyway, there must be an easier way to do this. I think I used some things the book hadn't taught yet.

Thanks!

Originally Posted by Truthbetold

Find the measure of angle A if 5 times the complement of angle A is 150 greater than the supplement of angle A.

I have this
Let s be supplement and c be complement.
180-A = s
90-A= c


5c-150= s
I plugged the above in.

5c-150=180-A
Then plugged in my definition for c.
5(90-A) - 150 = 180 - A
450-5A + A=180 + 150
-4A=330-450
-4A=-120
A= 30.

Huh. That's strange I got it right this time.
ANyway, there must be an easier way to do this. I think I used some things the book hadn't taught yet.

Thanks!

You have the right answer and, no, there isn't an easier way to do this. You did it just fine!

-Dan