Why would you ever need to find the percent of a number?

Percentages are important for understanding the financial aspects of everyday life. ... The symbol for percent is % and its similarity to /100 reminds us of its meaning. Percentage is another way to write fractions with a denominator of 100. For example, 8% means .

Step-by-step explanation:

You'll use percentages for the rest of your life. ... Percentages are used to figure out how much money we need to put 10% down on an apartment, how much we'll pay for the 6.25% sales tax

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