document.write( "Question 472968: How do you find the slant height and base edge of a regular square pyramid when the height is 6 and the lateral edge is 10? \n" ); document.write( "
Algebra.Com's Answer #324355 by Theo(13342)![]() ![]() You can put this solution on YOUR website! You have a reguar square pyramkid. \n" ); document.write( "The base is square. \n" ); document.write( "The height is 6. \n" ); document.write( "The lateral edge is 10. \n" ); document.write( "Here's a reference that tells you all sorts of things related to pyramids. \n" ); document.write( "One of those things describes what the lateral edge is and tells you how to calculate it given the radius of the base and the height. \n" ); document.write( "http://www.vitutor.com/geometry/solid/pyramid_math.html \n" ); document.write( "In your problem, you are given the height and the lateral edge and you are asked to find the slant height. \n" ); document.write( "That's slightly different. \n" ); document.write( "The slant height would be the altitude of any of the lateral faces. \n" ); document.write( "Lateral face and slant face are the same as far as I can tell. \n" ); document.write( "Check the reference for a description of what a lateral face is. \n" ); document.write( "To find the slant height, you need to find the apothem of the base. \n" ); document.write( "To find the apothem of the base, you need to find the radius of the base. \n" ); document.write( "the picture below shows you what your pyramid will look like. \n" ); document.write( " ![]() \n" ); document.write( "AE is a lateral edge. \n" ); document.write( "AB is the height of the pyramid. \n" ); document.write( "BE is radius of the base of the pyramid. If you were to circumscribe a circle around the base of the pyramid, BE would be the radius of that circle. \n" ); document.write( "BG is the apothem of the base of the pyramid. If you were to inscribe a circle within the base of the pyramid, BG would be the radius of that circle. \n" ); document.write( "Angle x is the angle that you need to find the radius of the base. \n" ); document.write( "Angle x is angle AEB. \n" ); document.write( "The sine of angle x is equal to opposite / hypotenuse which is equal to AB / AE which is equal to 6/10 which is equal to .6 \n" ); document.write( "Angle x is equal to arcsine of .6 which is equal to 36.86989765 degrees. \n" ); document.write( "Cosine of angle x is equal to adjacent / hypotenuse which is equal to BE / AE which is equal to BE / 10. \n" ); document.write( "Multiply both sides of this equation by 10 and you get 10 * cosine of angle x is equal to BE. \n" ); document.write( "This makes BE equal to 8 as shown in the diagram. \n" ); document.write( "You now have enough information to find BG which is the apothem of the base. \n" ); document.write( "In order to find the apothem of the base, you need to know what angle y is. \n" ); document.write( "angle y is angle BEG. \n" ); document.write( "Since the base is a square, angle y is equal to 45 degrees. \n" ); document.write( "The sine of angle y is equal to opposite / hypotenuse which is equal to BG / BE which is equal to BG / 8. \n" ); document.write( "Multiply both sides of this equation by 8 to get: \n" ); document.write( "8 * sine (45) = BG. \n" ); document.write( "This makes BG equal to 5.65685425. \n" ); document.write( "You now have enough information to find the slant height. \n" ); document.write( "In order to do that, you need to find angle z. \n" ); document.write( "Angle z is angle AGB. \n" ); document.write( "The tangent of angle z is equal to opposite / adjacent which is equal to AB / BG which is equal to 6 / 5.65685425 which is equal to 1.060660172. \n" ); document.write( "The arc tangent of 1.060660172 is equal to 46.68614334. \n" ); document.write( "Angle y is equal to 46.68614334. \n" ); document.write( "You can now find the slant height. \n" ); document.write( "The sine of angle z is equal to opposite / hypotenuse which is equal to AB / AG which is equal to 6 / AG. \n" ); document.write( "Multiply both sides of this equation by AG and divide both sides of this equation by sine (z) to get: \n" ); document.write( "AG = 6 / sine(z) \n" ); document.write( "Since z equals 46.68614334 degrees, this equation becomes: \n" ); document.write( "AG = 6 / sine (46.68614334) which is equal to 6 / .727606875 which is equal to 8.246211251. \n" ); document.write( "AG is equal to 8.246211251 which is equal to the slant height of your pyramid. \n" ); document.write( "The following picture shows you the details of each section of the pyramid as we progress from the start to the solution. \n" ); document.write( " ![]() \n" ); document.write( "Step 1 is where we find the radius of the base. \n" ); document.write( "Step 2 is where we find the apothem of the base. \n" ); document.write( "Stepo 3 is where we find the slant height of the pyramid.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |