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A flagpole casts a shadow 18 ft long. At the same time, Rachael casts a shadow that is 4 ft long. If Rachael is 5 ft tall, what is the height of the flagpole?
 Jan 29, 2012

Best Answer 

 #1
avatar+3146 
+8
Quote:

A flagpole casts a shadow 18 ft long. At the same time, Rachael casts a shadow that is 4 ft long. If Rachael is 5 ft tall, what is the height of the flagpole?



if you can't remember the "Intercept theorem", see the sketch how to get to the formula:
α = tan( 5ft/4ft )
α = tan( x / 18ft )
=>
tan( 5ft/4ft )=tan( x / 18ft ) |atan()
5ft/4ft=x/18ft |*18ft
x=18ft*5ft/4ft

[input]x=18ft*5ft/4ft in ft[/input]
 Jan 29, 2012

5+0 Answers

 #1
avatar+3146 
+8
Best Answer
Quote:

A flagpole casts a shadow 18 ft long. At the same time, Rachael casts a shadow that is 4 ft long. If Rachael is 5 ft tall, what is the height of the flagpole?



if you can't remember the "Intercept theorem", see the sketch how to get to the formula:
α = tan( 5ft/4ft )
α = tan( x / 18ft )
=>
tan( 5ft/4ft )=tan( x / 18ft ) |atan()
5ft/4ft=x/18ft |*18ft
x=18ft*5ft/4ft

[input]x=18ft*5ft/4ft in ft[/input]
admin Jan 29, 2012
 #2
avatar+247 
0

9 I think lol I'm in 5th grade so idk math like this.

 Nov 29, 2014
 #3
avatar
0

flag pole height 22'6"

 Feb 17, 2015
 #4
avatar+129852 
+5

We can solve this using similar triangles

5 / 4 = x / 18     multipy both sides by q8

18(5 / 4) = x = 22.5 ft  = 22 ft 6 in.

 

 Feb 17, 2015
 #5
avatar
0

Hello ??

 Jan 30, 2016

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