i cant understand Cylindrical Coordinates!!!?
826982
If the point is in the yz-plane, it has x=0. In other words, its projection on the xy-plane lies on the y-axis. But that means that the angle theta is *not* zero but either Pi/2 (when y>0) or 3Pi/2 (when y<0).
477554
If you assume that at the bottom left corner the coordinates are i = 0, j= 0. and at the other end (18,0).\nT has to be:\nT = 18/7.5\n\nFor Y coordinate, it must be zero:\n12t - 5t^2 = 0\nt = 0, or 12/5\n\nso 12/5 = 18/7.5 which is at the bottom right (18,0) and proves the question.
979191
When converting from rectangular coordinates to polar coordinated, remember the following.\n\n@ = Theta\nx = r*cos(@)\ny =r*sin(@)\n\nr^2 = x^2 +y^2\n\ntan(@) = y/x\n\nso your equation\nx^2 +y^2 =36 becomes\nr^2 = 36   OR\nr =6 (which is a circle with radius 6)
257038
Cylinder: (pi)*(radius^2)*(height)\nPrism: (area of the base)*(height)
706522
It's often handy to draw yourself out a little sketch.  From it you can see the location of the given point.\n\nTo identify the angle the given point makes with the x-axis and the y-axis use trigonometry.  Switch to radians.\n tan Θ = opp./ adj.\n Θ = tan^-1 opp./ adj.\n Θ = tan^-1 (-0∙4425./ -0∙8968)\n Θ = tan^-1 (-0∙493 210 52)\n Θ =  0∙458 370 613 rad.\n    This is the value of the angle below the x-axis.  You need to include the angle above the x-axis, which is 180º or π radians.\n Θ =  0∙458 370 613 rad. + π rad.\n Θ =  (0∙458 370 613 + 3∙14) rad.\n Θ =  3∙598 370 613 rad.\n Θ ≈  3∙6 rad.
390031
what????????? i cant understand
761667
cylinder\n1.volume=pir^2h\n2.LSA=2pirh\n3.TSA=2pir(h+r)\n\nsphere\n1.volume=(4/3)pir^3\n2.area=4pir^2\n\nhemisphere\n1.volume=(2/3)pir^3\n2.basearea=pir^2\n3.LSA=2pir^2\n4.TSA=3pir^2\n\ncone\n1.volume=(1/3)pir^2h\n2.LSA=pirl\n3.TSA=pir(l+r)\n\ncube\n1.volume=a^3\n2.surface area=6a^2\n\ncuboid\n1.volume=lbh\n2.surface area=2(lb+lh+bh)
30751
The Edifier has it right, but darned if I can follow the notation. You really need to see this written out like a textbook to understand what's going on.\n\nClick the link below in "sources" to see the answer hosted at my website www.calculus-help.com. Right now, Yahoo! answers, as far as I can tell, doesn't allow graphics, which makes it tricky to answer ANY math questions.\n\nPlease don't post math answers, guys, if the poster knows the answer but can't get there, and you get something completely different.
746093
It's straight ahead geometry.\nDraw a circle with center O.  Draw a diameter horizontally through the circle. Label the left intersect as A and the right intersect as B.  Now draw a vector from O to a point P on the circle.  What tdo you know about triangles AOP and BOP in terms of the angle the vector makes with the diameter?  Use law of sines, law of cosines, trig, etc. to show that angle APO and angle BPO add up to 90 degrees and your done.\n\n\nDoug
215612
C = 2 pi r\nif d = 24.2, r = 12.1\n\ntherefore C = 2 x pi x 12.1\n            = 76.03\n\nFor all the guys think i shud get a keyboard whacked on my head i explained how it shud be worked out and didnt just giv d answer. \n\nInstead of saying rubbish i suggest u at least confirm that my answer is correct!!
450833
join the 2 pointz frm da arc vit da radius.measure out da value of da angle forned here.then substitute da values 4 this formula:  2*pie*radius/da angle u measured\n\nhappy solvin!
970313
r=radius\nd=diameter\n\n1 C=2r(pi)\n2 C=d(pi)\n\n(Same thing because 2r=d)
610972
considering both y values are -2 for A and C....\n\nwe know that a straight line exists between these two points, which means that it HAS to be 1 of the 4 sides.\n\ngiven that, the coordinates or K and L HAVE to be (3, infinity (EXCEPT -2)) and (-4, infinity (EXCEPT -2))
703288
Cool geometry im learning this in class 2bad i cant help u cuz im faling -.-
481336
well, ok, i see lots of complicated answers...but here is the answer in simple terms\n\nthe radius measures teh distance from the center to its boundry...it doesnt matter what the coordinates of teh boundry are because we have to use the distance formula to find it which is\n\nd = sqrt[(x-x1)^2 +(y-y1)^2]\n\nso from this equation (x1,y1) is the origin (0,0)\n\nso you really have\n\nradius = d = sqrt[x^2 + y^2]\n\nso whatever point you choose the distance must be positive because any numbers squared then added will be positive.\n\nso you would claim, well what if the center wasnt at the origin, well the only difference would be that you would use the original distance equation i mentioned.\n\nSo we can say that all distance (according to the distance equation) must be positive, try it with any points you like, it will always be positive.  Due to the distance equation always being positive, all radii must be positive.\n\nhope this helps\n\nmatttlocke\n\nPS\nand for everyone who says distance cant be negative...they lie\n\nthe magnitude of direction can never be negative the negative does imply direction.  for example, on the number line, we have points -5, and 5, the distance of both of those points from 0 is 5, but if we were plot each point they would be going in opposite directions, and we know this due to the negative sign\n\nso the distance formula means that the distance will always be positive, the negative does tell you direction, ask any mathematician (im working on that) or a physicist and they will tell you the same thing.\n\nBut, a negative and positive radius mean the same thing because the boundry of the circle will intersect all the points at whatever the measure of the radius is in all directions, so i spose you could look at it as negative, but it doesnt really matter.  This would all hold in any 'n' dimension.
624334
Example: Find the length of a helix which winds three times around a cylinder of height 12" and radius 3"\n\nAnswer: divide the cylinder into three sections. The helix goes once around a cylinder of height 4" and radius 3"\n\nThe surface of the cylinder can be "peeled" into a rectangle 4" by 2 * pi * 3" = 18.850". The helix is a diagonal of that rectangle. So its length is sqt(4^2 + 18.850^2) = 19.27"\n\nIt goes around the cylinder three times and its total length is therefore 57.81"
1128048
Regarding your edit... y = 90º is wrong. All the rest have shown the process, and they are right. With tthat figure, y = 108º