document.write( "Question 33691: A regular Pentagon ABCDE is incribed in circle O. Chords EC and DB intersect at F (not diameter). Chord DB is Extended to G (outside circle), and Tangent GA is drawn.
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document.write( "find measure of angle BDE
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document.write( "find measure of angle BFC
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document.write( "find measure of angle AGD \n" );
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Algebra.Com's Answer #20107 by venugopalramana(3286)![]() ![]() You can put this solution on YOUR website! A regular Pentagon ABCDE is incribed in circle O. Chords EC and DB intersect at F (not diameter). Chord DB is Extended to G (outside circle), and Tangent GA is drawn. \n" ); document.write( "find measure of angle BDE \n" ); document.write( "find measure of angle BFC \n" ); document.write( "find measure of angle AGD \n" ); document.write( "HOPE YOU HAVE A FIGURE OF THE ABOVE..ASSUMING THAT I AM GIVING THE SOLUTION. \n" ); document.write( "SUM OF ALL INTERIOR ANGLES IN A PENTAGON =(2*5-4)*90 =540 \n" ); document.write( "SINCE IT IS REGULAR PENTAGON EACH ANGLE =540/5=108 \n" ); document.write( "AS PER GIVEN DATA,A,B,E,D LIE ON A CIRCLE...SO ABED IS A CYCLIC QUADRILATERAL..HENCE SUM OF OPPOSITE ANGLES=180=ANGLE EAB+ANGLE BDE \n" ); document.write( "BUT ANGLE EAB=108 AS PROVED ABOVE \n" ); document.write( "----------------------------------------- \n" ); document.write( "HENCE ANGLE BDE=180-108=72 \n" ); document.write( "------------------------------------------- \n" ); document.write( "SIMILARLY FROM CYCLIC QUADRILATERAL ECBA,WE GET ANGLE ECB=72 \n" ); document.write( "NOW IN A REGULAR PENTAGON EACH SIDE SPANS 1/5 OF PERIMETER OF CIRCUM CIRCLE WITH O AS CENTRE.HENCE EACH SIDE SUBTENDS AN ANGLE OF 360/5=72 AT CENTRE AND HALF OF THAT THAT IS 36 AT THE CIRCUMFERENCE.. \n" ); document.write( "HENCE ANGLE ADB=ANGLE DBC =36 \n" ); document.write( "NOW IN TRIANGLE CFB...WE HAVE... \n" ); document.write( "ANGLE FCB =ANGLE ECB =72..PROVED ABOVE. \n" ); document.write( "ANGLE FBC=ANGLE DBC=36......PROVED ABOVE \n" ); document.write( "-------------------------------------------- \n" ); document.write( "HENCE ANGLE BFC=180-72-36=72 \n" ); document.write( "-------------------------------- \n" ); document.write( "ABDE IS A CYCLIC QUADRILATERAL...AB IS A CHORD...AG IS A TANGENT TO CIRCUM CIRCLE..HENCE ANGLE BAG = ANGLE IN THE OPPOSITE SEGMENT =ANGLE ADB=36..PROVED ABOVE \n" ); document.write( "HENCE ANGLE EAG=ANGLE EAB + ANGLE BAG=108+36=144 \n" ); document.write( "IN QUADRILATERALDEAG...WE HAVE \n" ); document.write( "ANGLE AGD=360-ANGLE EDB-ANGLE EAG-ANGLE DEA \n" ); document.write( "=360-72-144-108=36 \n" ); document.write( "-------------------------- \n" ); document.write( "HENCE ANGLE AGD=36 \n" ); document.write( "------------------------------- \n" ); document.write( " |