document.write( "Question 1196783: The sides of a parallelogram ABCD are AB= 424mm and AD= 348mm
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document.write( "If angle ABC is 130°\r
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document.write( "a. Find the lengths of long and short diagonals.
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document.write( "b. Find the area of and perimeter of a parallelogram \n" );
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Algebra.Com's Answer #829775 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Part (a)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Diagram: \n" ); document.write( " ![]() \n" ); document.write( "Draw a segment from A to C. This is the longer diagonal.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Focus on triangle ABC \n" ); document.write( "Side 'a' is opposite angle A \n" ); document.write( "Side 'b' is opposite angle B \n" ); document.write( "Side 'c' is opposite angle C\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "For triangle ABC, we have \n" ); document.write( "a = 348 \n" ); document.write( "b = unknown \n" ); document.write( "c = 424 \n" ); document.write( "angle B = 130 degrees\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Apply the law of cosines. \n" ); document.write( "Make sure your calculator is in degree mode. \n" ); document.write( "b^2 = a^2+c^2 - 2*a*c*cos(B) \n" ); document.write( "b^2 = 348^2+424^2 - 2*348*424*cos(130) \n" ); document.write( "b^2 = 490,569.194768937 \n" ); document.write( "b = sqrt(490,569.194768937) \n" ); document.write( "b = 700.406449691132 \n" ); document.write( "The longer diagonal (AC) is approximately 700.406 mm long\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Return to the original parallelogram diagram shown at the top. Draw a line from B to D to form triangle ABD\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Angle DAB is 180-(angleABC) = 180-130 = 50 degrees \n" ); document.write( "This is angle A of triangle ABD\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have this info about triangle ABD \n" ); document.write( "side b = 348 \n" ); document.write( "side d = 424 \n" ); document.write( "angle A = 50 degrees\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use the law of cosines \n" ); document.write( "a^2 = b^2+d^2 - 2*b*d*cos(A) \n" ); document.write( "a^2 = 348^2+424^2 - 2*348*424*cos(50) \n" ); document.write( "a^2 = 111,190.805231063 \n" ); document.write( "a = sqrt(111,190.805231063) \n" ); document.write( "a = 333.452853085802 \n" ); document.write( "The shorter diagonal (BD) is approximately 333.453 mm long\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "=============================================================================================\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Part (b)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "AB = CD = 424 \n" ); document.write( "AD = BC = 348\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Area = side1*side2*sin(included angle) \n" ); document.write( "Area = AB*BC*sin(angle ABC) \n" ); document.write( "Area = 424*348*sin(130) \n" ); document.write( "Area = 113,031.389671091 square mm approximately\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Perimeter = AB+BC+CD+AD \n" ); document.write( "Perimeter = AB+AD+AB+AD \n" ); document.write( "Perimeter = 2*AB + 2*AD \n" ); document.write( "Perimeter = 2*(AB + AD) \n" ); document.write( "Perimeter = 2*(424 + 348) \n" ); document.write( "Perimeter = 2*(772) \n" ); document.write( "Perimeter = 1544 mm \n" ); document.write( " \n" ); document.write( " |