a tree 10.5 ft tall cast a shadow 11.5 ft. long. what is the height that cast a shadow 17.5 ft. long

Question

like I really don't know what to do I really need a quick response

Answer 1

This would be a proportion.  The trees and their shadows form similar triangles so their sides will be proportional

 

H₁=H₂

S₁   S₂

 

where H₁ is the height of the first tree, H₂ is the height of the second tree, S₁ is the length of the first tree's shadow and S₂ is the length of the second trees shadow.  

 

Cross multiply and you get

 

H₁S₂=H₂S₁

 

Divide both sides S₁ to solve for H₂ and you get

 

H₂=H₁S₂

         S₁

 

Plug in H₁=10.5, S₂=17.5, and S₁=11.5 and you get H₂=15.98ft