document.write( "Question 463054: how to find the measures of the consecutive angles of a quadrilateral in the ratio form of 5:7:11:13. How do you find the measure of each angle, draw a quadrilateral, and explain why two sides must be parallel? \n" ); document.write( "
Algebra.Com's Answer #317331 by Theo(13342) You can put this solution on YOUR website! the sum of the angles of a quadrilateral = 360.\r \n" ); document.write( "\n" ); document.write( "since your angles are in the ratio of 5:7:11:13, you can use the general formula of 5x + 7x + 11x + 13x = 360 to solve for x and, from that, to derive each angle.\r \n" ); document.write( "\n" ); document.write( "you get 36x = 360 which gets you x = 10 degrees.\r \n" ); document.write( "\n" ); document.write( "this makes your angles 50, 70, 110 and 130 respectively.\r \n" ); document.write( "\n" ); document.write( "label your quadrilateral starting from the top left and working to the top right and then to the bottom right and then to the bottom left ABCD.\r \n" ); document.write( "\n" ); document.write( "A is top left \n" ); document.write( "B is top right \n" ); document.write( "C is bottom right \n" ); document.write( "D is bottom left\r \n" ); document.write( "\n" ); document.write( "Angle A is 50 degrees \n" ); document.write( "Angle B is 70 degrees \n" ); document.write( "Angle C is 110 degrees \n" ); document.write( "Angle D is 130 degrees.\r \n" ); document.write( "\n" ); document.write( "Extend AB a little more to the right and stop at E.\r \n" ); document.write( "\n" ); document.write( "You have angle ABC which is equal to 70 degrees. \n" ); document.write( "You have angle EBC which is the supplement of ABC which is equal to 110 degrees.\r \n" ); document.write( "\n" ); document.write( "The sides that will be shown to be parallel are sides AB and CD.\r \n" ); document.write( "\n" ); document.write( "The line BC is a transversal that intersects both AB and CD.\r \n" ); document.write( "\n" ); document.write( "The 2 alternate interior angles of these intersections are angles EBC and angle BCD.\r \n" ); document.write( "\n" ); document.write( "Both these angles are 110 degrees.\r \n" ); document.write( "\n" ); document.write( "If the alternate interior angles of 2 lines cut by a transversal are equal, then the lines are parallel. This is either a theorem or a postulate that you should be able to find in your geometry text.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "You can also prove AB is parallel to CD by extending line CD further to the left to stop at F.\r \n" ); document.write( "\n" ); document.write( "The angle ADC is 130 (previously called angle D).\r \n" ); document.write( "\n" ); document.write( "The angle ADF is equal to 50 degrees (supplement of 130 degrees).\r \n" ); document.write( "\n" ); document.write( "Angle BAD = 50 degrees and angle ADF = 50 degrees.\r \n" ); document.write( "\n" ); document.write( "These are alternate interior angles and they are equal, therefore the lines AB and CD are parallel to each other.\r \n" ); document.write( "\n" ); document.write( "A picture of the arrangement is shown below:\r \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( " |