Mathematics
OpenStudy (anonymous):

a tree casts a shadow 24 feet long. at the same time, a vertical rod 20 feet high casts a shadow 12 feet long. How tall is the tree???

OpenStudy (anonymous):

okay lets take this one step at a time. a 20 feet high rod casts as 12 foot shadow. what is the length of the shadow of the tree?

OpenStudy (anonymous):

set up a ratio

OpenStudy (anonymous):

it is 24 feet. 24 feet is two times 12 feet. so the shadow of the tree is twice the length of the shadow of the rod. what does this tell you about the height of the tree in relation to the height of the rod?

OpenStudy (anonymous):

still lost

OpenStudy (anonymous):

OpenStudy (anonymous):

does this mean that the tree is 48 feet tall???

OpenStudy (anonymous):

OpenStudy (anonymous):

so what would it be???

OpenStudy (anonymous):

40 feet 12x =20*24 = 40

OpenStudy (anonymous):

$x \over 24$ = $20 \over 12$ and corss multiply

OpenStudy (anonymous):

cross*

OpenStudy (anonymous):

thank you so much it was right!!!