Last visit was: 13 Jun 2024, 22:46 It is currently 13 Jun 2024, 22:46
Toolkit
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

# A ladder 20 feet long is placed against a wall. If the distance on the

SORT BY:
Tags:
Show Tags
Hide Tags
Math Expert
Joined: 02 Sep 2009
Posts: 93696
Own Kudos [?]: 631586 [1]
Given Kudos: 82279
Senior Manager
Joined: 21 Dec 2021
Posts: 324
Own Kudos [?]: 245 [3]
Given Kudos: 242
GMAT Tutor
Joined: 24 Jun 2008
Posts: 4128
Own Kudos [?]: 9360 [3]
Given Kudos: 91
Q51  V47
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6814
Own Kudos [?]: 30532 [2]
Given Kudos: 799
Re: A ladder 20 feet long is placed against a wall. If the distance on the [#permalink]
2
Kudos
Top Contributor
Bunuel 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

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

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
VP
Joined: 16 Feb 2015
Posts: 1071
Own Kudos [?]: 1043 [1]
Given Kudos: 30
Location: United States
Re: A ladder 20 feet long is placed against a wall. If the distance on the [#permalink]
1
Kudos
Explanation: