CPhill

tan(22°) = 450 / d       where d is the distance to the building......rearrange

d  = 450 / tan(22°)  =  about 1114 ft

Notice that  any non-zero rational   (a/b)^-n  can always be written as (b/a)ⁿ   

So.........

[-1/2] ^-3   = [ -2/1] ³   =  [-2]³   =  - 8

I don't have a "mathematical proceedure" for solving this, but....there are some clues as to what the answer might be.....

First.......since you bought 72 tins, the ending digit must be even......Secondly, since 72 is divisible by 3, the sum of the digits of the total price must be divisible by 3.

Let the final digit = 0........then, the possibilties in this case might be that  the price was either $267.90, $567.90  or $867.90.....unfortunately......none of these give a non-repeating answer

Let's say the final digit = 2.........the the possible prices are either $367.92, $667.92  or $967.62

And I think you will find that $367.92 produces the correcf price of $5.11  per tin........

What line???

Post your question.....we'll see if we can help.......

-36 = 7x - 6    add 6 to both sides

-30  = 7x    divide both sides by 7

-30 / 7 =  x

15/25 = 3/5 = 0.60  =  60%

Take the cosine inverse [ arccos]  of 1/2

arccos (1/2)   =  pi/3 ....  or 60°

1 / 3    >    1 / 4

side = sqrt128)

diagonal  =  sqrt (2) * side  =  sqrt(2)*sqrt(128)  =  sqrt(256)  = 16 m