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A ladder 20 feet long is placed against a wall. If the distance on the
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02 Feb 2022, 05:30
02 Feb 2022, 05:30
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A ladder 20 feet long is placed against a wall. If the distance on the ground from the wall to the ladder is 12 feet, how many feet up the wall does the ladder reach?
A 12
B 15
C 16
D 21
E 24
A 12
B 15
C 16
D 21
E 24
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Re: A ladder 20 feet long is placed against a wall. If the distance on the
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03 Feb 2022, 12:12
03 Feb 2022, 12:12
Carcass wrote:
A ladder 20 feet long is placed against a wall. If the distance on the ground from the wall to the ladder is 12 feet, how many feet up the wall does the ladder reach?
A 12
B 15
C 16
D 21
E 24
A 12
B 15
C 16
D 21
E 24
Here's what's happening (the ladder is blue)
Since the wall is perpendicular to the ground we can use the Pythagorean theorem to find the value of x
We get: x² + 12² = 20²
Simplify: x² + 144 = 400
This means: x² = 256
So, x = 16
Answer: C
Alternatively, if you recall the Pythagorean triple 3-4-5, you might recognize that the two give sides of our diagram are each 4 times the values in the Pythagorean triple.
In other words 20 = 4(5), and 12 = 4(3)
So, we can conclude that x = 4(4) = 16
Answer: C
gmatclubot
Re: A ladder 20 feet long is placed against a wall. If the distance on the [#permalink]
03 Feb 2022, 12:12
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