Question 224584
A rectangle is 4 cm longer than it is wide, and it area is 117 cm squared. Find its dimensions.


Step 1.  Let w be the width


Step 2.  Let w+4 be the length


Step 3.  Let Area A=w(w+4)=117 where the area is the product of the length and the width.


Step 4.  Then {{{w^2+4w-117=0}}} where we subtracted 117 from both sides of the equation to get a quadratic equation.


Step 5.  To solve, use the quadratic formula given as


{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}


where a=1, b=4 and c=-117


*[invoke quadratic "x", 1, 4, -117]


Selecting the positive solution we have w=9 then w+4=13 and A=9*13=117  which is a true statement.


Step 6.  ANSWER: The width is 9 cm and the length is 13 cm.


I hope the above steps were helpful.


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And good luck in your studies!


Respectfully,
Dr J

http://www.FreedomUniversity.TV