Juliet O’Hara works for a weekly paycheck. Last week she worked 5 days for a total of 39 hours. Her regular rate of pay is $10.95 an hour. In addition to federal income tax, state income tax, Medicare, and social security, Juliet also has insurance of $20 a week withheld and puts 4% of her gross pay into a retirement account. Compute her gross pay, deductions, and net pay

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4