SOLUTION: If the sides of a square are lenghtened by 8cm, the area becomes 144 cm^2. Find the length of a side of the original square.
Which form of the quadratic equation would I use to
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-> SOLUTION: If the sides of a square are lenghtened by 8cm, the area becomes 144 cm^2. Find the length of a side of the original square.
Which form of the quadratic equation would I use to
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Question 184171: If the sides of a square are lenghtened by 8cm, the area becomes 144 cm^2. Find the length of a side of the original square.
Which form of the quadratic equation would I use to solve this problem? Found 2 solutions by ankor@dixie-net.com, Earlsdon:Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! If the sides of a square are lengthened by 8cm, the area becomes 144 cm^2.
Find the length of a side of the original square.
;
Let x = side of the original square
then
(x+8) = side of the larger square
:
(x+8)^2 = 144
Find the square root of both sides
x + 8 = 12
:
x = 12 - 8
:
x = 4 cm is the length of the original square
:
:
Check: (4+8)^2 = 144
:
:
If you absolutely have to have a quadratic equation:
Foil (x+8)^2
x^2 + 16x + 64 = 144
x^2 + 16x + 64 - 144 = 0
x^2 + 16x - 80 = 0
Factor
(x+20)(x-4) = 0
Positive solution is what we want:
x = 4 cm
You can put this solution on YOUR website! Let S be the length of the side of the original square.
The area of the original square is expressed by
When the side, S, is increased by 8cm, the length of the side of the new square becomes S+8 and the new area is expressed as: and this is equal to 144 sq.cm.
So you can set up the equation to solve for S... Subtract 144 from both sides. Factor this quadratic equation. Apply the zero product rule: or so... or Discard the negative solution as the length must be a positive value.
The length of the side of the original square is 4cm.
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