A 20ft. flagpole casts a shadow 12ft long. How tall is a nearby building that casts a shadow 20ft long?

Question

Geometry 

Answer 1

Hello, Robin,

 Note:  You have two items here, a flagpole and a nearby building.  Each have a shadow.  The shadow is always on the ground.  A building and a flagpole stand upright.

1.  Draw a picture.      2.  Label it.       3. Set up a proportion.    4.  Cross multiply and simplify.

                    |\

20 |\          x |  \                 Q:  How tall is the building?_____You have an unknown.  Call it "x."

    |_\            |__\

    12 ft.          20 ft.

 

Proportion:      height of flagpole   =     Height of building

                               shadow                           shadow

                  

                                        20              =        x             20*20 = 12(x)

                                        12                       20

I will let you finish you problem.  Susan C.

Answer 2

20/12=x/20 => 5/3 = x/20 => 3x = 100 => x =33 1/3