If an angle is 18 degrees less than twice its complement, how do you find the ratio of the angle to its complement?

1 Answer
May 2, 2015

Let's call the angle we seek #alpha#

Then the complement is defined as #90^o-alpha#
And twice the complement would then be:
#2*(90^o-alpha)=180^o-2alpha#

So the equation turns into:
#alpha=(180^o-2alpha)-18^o=162^o-2alpha->#
Add #2alpha# to both sides, later divide by #3#:
#3alpha=162^o->alpha=54^o#

Check your answer :

If #alpha=54^o->#complement=#36^o#
Twice complement=#72^o#
Difference=#18^o# Check!