Help needed from those who are good in math

To Continue my post above:

You should draw all this out as a point in the middle of square surrounded by a circle. The circle is touching the corners of the square.

Area of a circle equation is (pi)*radius^2

Side of the square from the garden is square root of 920. That number is 30 since this is all whole number work.
To find the radius of the circle, we can assume since this figure is a square garden that if two intersecting lines went through the center the angles formed at the center would be 90 degrees(right angles) to each other. This forms 4 triangles in the square. You can the use the "sine" functino for this problem.
In a right triangle, there is a 90* angle, and two 45* angles. Match these up. Sine is opposite side over the hypotenuse.
The longest side has the greatest angle.

So its' sin(45*) = X/30.
.707 = X/30
X = (.707)(30) = 22

So the radius equals 22 and that the shortest radius one can have to water the whole garden.

TO Find the area that is not being watered but is just extra, it's the area of the circle MINUS the area of the square garden.

Area of Circle = (pi)(radius^2)
Area of Square = side^2

so it's (3.14)(21^2) - 30^2 = 485 square feet not being watered

There you go my man. It's not about derivatives at this level, use the easy math for easy problems.

If it was a harder problem, then use the calculus.

Dave

"b) what radius gives the least amount of material?
Use your brains and calculate it out just punching numbers basically to solve for the V=100"

OK, YA.

1 + 1 = Jello

Ha im glad im not at school anymore. Btw that kind of question in a maths class makes me think you are still at high school and aint 18 years old, naughty naughty.

Damn, why does everyone seem to think I am in high school cause I ask a math question? There must be many here who are proficient in geometry in their adult lives. Oh well, I am not. Didn't get it then, still don't get it now. I am 28 years old, and in a college level MAT 140 class. Don't worry, I will direct any further questons to a homework helpsite to avoid any further issues. But just so you know........there are people past 18 who are still in school, usually it is called college, and not everyone is great at every subject there is.

To those who have offered assistance, without assuming I am under 18--thank you very much, it is much clearer now, and I appreciate it very much, especially since some of the responses looked time consuming.

BTW, I currently have a 4.0 GPA, and would like to keep it that way, which is why I asked for help. Additionally I know there are some very knowledgeable people on this site, and thought I may be able to receive more assistance than our ambiguous instructor could provide.

Im sorry, didnt mean to offend

Is okay, wasn't really U. It's just that was not the 1st comment I got where it was assumed I was still in high school. Didn't mean to rant too much.