+0

# Pole

+8
2700
5
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

#1
+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

#1
+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]
#2
0

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

Nov 29, 2014
#4
+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