![]() On the other hand, A_l denotes the lateral area, meaning the total area of the four lateral faces. Note that A_b denotes the surface area of a single base of our prism. h – the lateral edge length (also called the height of the prism).Let's start with the notation we use for them and for the other values in our surface area of a rectangular prism calculator: To see what is the surface area of a rectangular prism, we need to know all three of its sides. Time to put the high-brow words aside and focus on how to find the surface area of a rectangular prism. Lastly, the sides of each rectangle are called edges (again divided into base edges and lateral edges). The bottom and top faces of the box are called bases, and each of the other four is called a lateral face. Note that this, in particular, means that there are three pairs of identical faces placed on opposite sides of the solid.Īlso, as with any other scientific definition, there are a few fancy names associated with the prism. Well, that is a rectangular prism! Or do you remember those drawings of houses that we did in kindergarten? Remove the angular roof, and you're left with another example of a rectangular prism.įormally (mathematically), a right rectangular prism is a solid where all six sides are rectangles that are perpendicular to one another. A regular, rectangular box, just like the ones you see in the supermarket, full of whatever products. Thus, the point we have found is a local minimum.Before we see what the surface area of a rectangular prism is, we should get familiar with the prism itself. The second derivative of this guy is strictly positive for positive s, implying the function is concave up for positive s. To do so you must take the second derivative. We'll end up with h = 2 * 5 2/3 *7 1/3 / sqrt(3).ĮDIT: It's a bit pedantic, but technically you have to make sure that it's a local minimum at the value of s that I've found. From there, we can easily find the height by substituting into our previous formula. We want to find the minimum so we set SA' = 0. SA = 2(sqrt(3)/4)s 2 + 3sh (the first term is the 2 triangular parts and the second term is the three lateral, rectangular parts).Īs a function of s alone, we have SA = 2(sqrt(3)/4)s 2 + 4sqrt(3)350/s. This is equivalent to h = 4*350/(sqrt(3)s 2 ). V = (sqrt(3)/4)hs 2 = 350 cm 3 (I converted mL to cm 3 for ease). Then the area of the base is (sqrt(3)/4)s 2. Let s be the base of the triangle and h be the height. This is an ordinary optimization problem so it requires the use of basic calculus. Re-read your post before hitting submit, does it still make sense.Show your work! Detail what you have tried and what isn't working.Use proper spelling, grammar and punctuation. ![]() Give context and details to your question, not just the equation.Help others, help you! How to ask a good question Asking for solutions without any effort on your part, is not okay. Beginner questions and asking for help with homework is okay. ![]() Post your question and outline the steps you've taken to solve the problem on your own.
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