What's the best way to work out the area of a 3d object?
353664
find the area of the cross section.... then times the area by the length... that is of course if it's a prism
598391
First find the area of the circle that is on the top or bottom of the cylinder. The area formula for a circle is \n\n"pi,r squared. That means multiply pi times the radius of the circle which you have to square first.\nThen you take the number that you get and multiply it by the height of the cylinder.\nGood luck.
956315
The simplest way is to cut it into five slices, each with an arc of 72 degrees (or 2*pi/5 radians). You could probably also figure out a way to cut it into strips so that each strip has equal area, but that would be significantly more complicated.
287728
Surface Area = [Base Area] +\n1/2 × Perimeter × [Side Length]\n\nVolume = 1/3 × [Base Area] × Height\n\nThe Surface Area has two parts: the area of the sides (the Lateral Area) and the area of the base (the Base Area). \n\nThe Base Area depends on the shape, there are different formulas for triangle, square, etc. \n\nBut the Lateral Area is surprisingly simple. Just multiply the perimeter by the side length and divide by 2. This is because the sides are always triangles and the triangle formula is base times height divided by 2
599733
I believe it would be one-half times the length of each diagonal.\n\nIn other words, if the diagonals are 4 & 6 the area would be:\n\nA = 1/2 * 4 * 6 = 12\n\nIf you don't know the diagonals, but you know the length of the sides, you could construct the diagonals and calculate their dimensions using the Pythagorean theorem:  c^2 = a^2 + b^2, and then solve from there.  Keep in mind that you'll have to do some extra geometric analysis to find the length of each leg of the right triangles that are created by the intersection of the diagonals before you can use the theorem.
70150
so you have to find the surface area of a cylinder that is 35diameter and 40 ft tall. or \n((3.14)17.5^2)40)
626725
First you need the area of a single face, to do this you need to multiply one side of the face (square) by another adjacent (next to) to the first, this will give you the area if a single face; then you just need to multiply that times six wich is the number of faces in a cube. Depending on the mesuring system that you are using, i.e. metric, standard, etc., you will end up with a number followed by cm.2 or ft.2, that "2" means that you are talking about area and not distance nor volume or any other; it avoids confussion.
501756
length x width = area\n3 x 6 = 18
953741
Just break the pentagon up into 5 triangles.  You can then add together the area of the 5 triangles to get the total area.
135768
Area = Pi times the radius squared (A=pr2)\nIf you need to know how to find the radius, go here:\n\nhttp://math.about.com/library/blcircle.htm
701955
You could use graph paper to get a good approximation of the surface area. Using a large circle would increase the accuracy.\nCount the whole squares, then count the half squares. \n\nAlternatively would be to use graph paper, then precisely cut out the circle, then cut the graph paper. On another sheet of graph paper, try to fill squares with the incomplete pieces from the circle.\n\nModifying Mike's answer, using a sensitive microbalance, find an average mass of one graph square then measure the mass of the cut out circle.
239138
well you could split up the thing into triangles. you know what the base is (1m) and the height is unknown, so lets call it h for now. so for each side, the area of the triangle is h/2 (bh/2 and b=1 so h/2). so for every 2 sides, the area is h. so the total area is 18h. \n\nso to find h, you have to use some trig. the equation to find the internal angles is (n-2)*180/n. cuz the sum of the internal angles is (n-2)*180. and then to find each angle, you have to divide by number of angles (which is same as number of sides). so in this case 34*180/36 = 170 degrees each angle. so now for each side, if you make a triangle with the center of the polygon, u should notice that the triangle is isosceles and the base angle is half of the side angle. \nas in the bottom 2 angles are equal and they are equal to 170/2. which is um 85. you can try this with any polygon if you dont believe it. try a square, (n-2)*180 = 2*180 = 360 is the sum of the internal angles. so each angle is 360/4 = 90 degrees. so if u connect each vertex to the center of the circle, you get 4 isosceles triangles and the base angles are 45 degrees each. \nso you have 85 degrees as the angle. so now if you split the isosceles triangle into 2 right angle triangles, you have 3 sides in each right angle triangle: the h, 0.5m and the line from the vertex to center. so you have the angle 85 degrees and you need h and you have the adjacent side = 0.5m. so you can use tan 85 = h/0.5 and you get h. \nso the total area is 18h. \n\ni really hope you understand that. its kinda hard to explain without drawing it out and showing you. if you need more help, then message me or somethin. later
517439
you can express the area as the sum of the areas of the 4 inner triangles which are each 1/2 base x height.  Each base is an edge of the quadrilateral.  The height can be determined in 2 ways and you will need both to solve the system of equations:\nfor example: to determine the height of APD, recognizwe that the height line splits APD into 2 right triangles.    Call the point where the height line intersects AD point E. The edge AD will be split between the 2 tringles proportionally:  AE = 24/69  AD and DE = 45/69 AD.  Now you can determine the height in terms of AD using pythagorean theorum.  Go from there...\n\nTry this site...
921006
Area = πab where a and b are the semi-major and semi-minor axis length
380933
Surface areas and lateral areas are always fun to find.  Surface areas for right prisms and cylinders is always the sum of the lateral area and two times a base.  (Lateral area is the sum of all the surfaces that aren't bases.)\n\nIn the case of a cylinder, the lateral area is really a rectangle - imagine cutting open a roll of toilet paper.  The length is really the circumference of the top (base) and the height is, well, the height of the roll.  So the lateral area is 2*pi*r*h.\n\nThe surface area is the lateral area plus two bases.  A base in this case is given by pi*r^2.  So the total surface area is 2*pi*r^2 + 2*pi*r*h.\n\nThe idea behind lateral and surface areas will carry over when you start working on right prisms (if you're not already doing those).  Lateral area is, in the case of a prism, the perimeter of the base (similar to cylinders, except we used "circumference" in place of "perimeter") times the height of the prism.  And the surface area is the lateral area plus two bases - in this case, the bases vary (you may have squares, triangles, trapezoids, etc.), so your formula for the total surface area will vary as well.\n\nThis is probably more than you wanted to know, but it's always good to relate things you know to things that you're learning.
270216
in a 2d object or representation, it would be the area. In a 3 dimensional object it would be the volume.
89513
There are so many way to find the area of the triangle, depends on what you know about that triangle.\n1, If you know the height and the base: the area is\nA=base*height*(1/2)\n\n2, If you know 2 sides of the triangle, and the angle in between that 2 sides.\nLet the 2 sides be (a) and (b), the angle be C.\nArea would be equal to\nA= a*b*sinC/2\n\n3, If you dont know any angle, but you know all 3 sides.\nLet 3 sides be equal to a, b, and c. Let s= (a+b+c)/2\nThe area can be calculated using:\nA= square root of [s*(s-a)*(s-b)*(s-c)]\n\n4, If you know all 3 angles, and 1 side of the triangle.\nLet the 3 angles be A, B and C, and the side be a which is opposite of angle A.\n\nA= (a^2*sinB*sinC) / (2*sinA)