In a rectangle ABCD the lengths of sides AB, BC, CD and DA are ( 5x + 2y + 2 )cm, (x + y + 4) cm, (2x + 5y - 7) cm, and (3x + 2y - 11) cm respectively Which of the following statements is / are true ?
A
One of the sides of the rectangle is 15 cm long
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B
Each diagonal of the rectangle is 39 cm long
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C
Perimeter of the rectangle is 102 cm
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D
Area of the rectangle is 560 cm2
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Solution
The correct options are A One of the sides of the rectangle is 15 cm long B Each diagonal of the rectangle is 39 cm long C Perimeter of the rectangle is 102 cm AD=BC AB=DC 3x+2y−11=x+y+4 5x+2y+2=2x+5y−7 2x+y=15..........................eq(1) multiplied by 3 3x−3y=−9..............................eq(2) on adding both equationswe get 6x+3y=45 3x−3y=−9 _____________________ 9x=36 x=4 puting x=4 in eq(1) 2×4+y=15 y=7 AB=5x+2y+2 =5×4+2×7+2=20+14+2=36 BC=x+y+4 =4+7+4=15 So, perimetre =2(36+15) =102 Area==36×15=540 Diagonal==√152+362=√1521=39 so a b c points are correct.