document.write( "Question 1036322: One acute angle of a right triangle is not less than 30° more than twice the other acute angle. What are the possible measures of the larger angle? \n" ); document.write( "
Algebra.Com's Answer #650990 by Theo(13342)![]() ![]() You can put this solution on YOUR website! let the 2 acute angles of the right triangle be represented by a and b. \n" ); document.write( "you get a + b = 90. \n" ); document.write( "if a is not less than 2b + 30, then a must be greater than or equal to 2b + 30. \n" ); document.write( "your equation is therefore a >= 2b + 30 \n" ); document.write( "since a + b = 90, then b = 90 - a and the equation becomes a >= 2 * (90 - a) + 30. \n" ); document.write( "simplify this is to get a >= 180 - 2a + 30. \n" ); document.write( "add 2a to both sides of the equation and combine like terms to get 3a >= 210. \n" ); document.write( "divide both sides of this equation by 3 to get a >= 70. \n" ); document.write( "if a >= 70, then b <= 20 because a + b = 90. \n" ); document.write( "let's see how this works. \n" ); document.write( "let's assume that a = 70. \n" ); document.write( "this means that b = 20 and we get 2 * 20 + 30 = 70. \n" ); document.write( "this satisfies the requirement that a is not less than 2 * b + 30 because a = 2 * b + 30, so we're good. \n" ); document.write( "now let's look at a = 71 degrees. \n" ); document.write( "this means that b = 19 degrees. \n" ); document.write( "a >= 2 * b + 30 means 71 >= 2 * 19 + 30 which means that 71 >= 68. \n" ); document.write( "this means that a is not less than 2 * b + 30 because a is greater than 2 * 19 + 30. \n" ); document.write( "looks like the requirements of the problem are satisfied. \n" ); document.write( "take any angle greater than or equal to 70 but less than or equal to 90 and the requirements of the problem will be satisfied. \n" ); document.write( "lets take one look at a smaler than 70. \n" ); document.write( "assume a = 69. \n" ); document.write( "this makes b = 21. \n" ); document.write( "2*b + 30 is equal to 42 + 30 = 72. \n" ); document.write( "in this case a < 2 * b +30 because 69 is smaller than 72, so we're not good since a is not greater than or equal to 70. \n" ); document.write( "the requirements are only satisfied when a is >= 70. \n" ); document.write( "your solution is that the possible measures of the larger angle are 70 <= a <= 90, where a represents the larger angle.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |