Look up the law of sines, I suggest Khan Academy. It is better if you know how to do it, it is very useful.
X^2-y^3=6
x^2-6=y^3
y= (x^2-6)^1 by 3
If x represents the length of the box, then 42-x will be the girth. Since the largest area for a given girth is that of a square, the side length of the square cross section is (42 -x)/4.
The volume as a function of package length is then
.. v(x) = x((42-x)/4)^2
This has a maximum at x=14. The corresponding volume is 686 in^3.
Answer:
$1,008 weekly, $52,416 annually
Step-by-step explanation:
14% of $7200 is 7200 multiplied by .14 (% is decimal multiplied by 100)
.14 of 7200 = 1008
Since you specified the year, I'm going to assume that you need the annual salary based on the weekly salary that she gets from commissions.
$1008 per week, 52 weeks in a year
52 * 1008 = $52416, her commission in 2011