Pedro bought a skateboard last week. The list price of the skateboard was $64.90. He has a 20% coupon. He has to pay 8.5% sales tax. What is total price of the skateboard with the discount, including tax? Round to the nearest cent if necessary.

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

answer: correct

step-by-step explanation:

114 plus 113 times 2 and 114 times 3