SOLUTION: A ladder is leaning against a wall. The distance from the bottom of the ladder to the wall is 3 feet less than the length of the ladder. Find the length of the ladder, if the dista

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Question 145407: A ladder is leaning against a wall. The distance from the bottom of the ladder to the wall is 3 feet less than the length of the ladder. Find the length of the ladder, if the distance of its top to the ground is 4 feet less than the length of the ladder.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A ladder is leaning against a wall. The distance from the bottom of the ladder to the wall is 3 feet less than the length of the ladder. Find the length of the ladder, if the distance of its top to the ground is 4 feet less than the length of the ladder.
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Using the formula a^2 + b^2 = c^2
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Let x = length of the ladder (c)
:
"The distance from the bottom of the ladder to the wall is 3 feet less than the length of the ladder." Therefore:
(x-3) = a
:
"the distance of its top to the ground is 4 feet less than the length of the ladder." therefore:
(x-4) = b
:
Using the formula we have:
(x-3)^2 + (x-4)^2 = x^2
FOIL
(x^2 - 6x + 9) + (x^2 - 8x + 16) = x^2
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Combine like terms on the left
x^2 + x^2 - x^2 - 6x - 8x + 9 + 16 = 0
:
x^2 - 14x + 25 = 0
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Solve for x using the quadratic formula;
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=1; b=-14; c=25
x+=+%28-%28-14%29+%2B-+sqrt%28-14%5E2+-+4+%2A+1+%2A+25+%29%29%2F%282%2A1%29+
:
x+=+%2814+%2B-+sqrt%28196+-+100+%29%29%2F%282%29+
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you can do the math here, the reasonable solution is x = 11.9' length of ladder
:
:
Check solution
8.9^2 + 7.9^2 = 141.6 which is 11.9 squared