math
posted by keisha on .
A tree casts a shadow 10 ft long. A boy standing next to the tree casts a shadow 2.5 ft long. The triangle sjown for the tree and its shadow is similar to the triangle shown for the boy and his shadow. If the boy is 5 ft tall, how tall is the tree?
I got 20 ft. I made a proportion 5/2.5=x/10. Is this right?

Yes, that's correct.