Question

A tree casts a shadow that measures 5 m. At the same time, a meter stick casts a shadow that is 0.4 m long. How tall is the tree?
Is this correct ?
1m=.4m
1m÷.4m =2.5m
2.5m X 5m =12.5m

Answer 1

they probably wanted you to set up 2 similar triangles and set up a ratio.

let the height of the tree be h m
then h/5 = 1/.4
cross-multiply to get .4h=5
h=5/.4 = 12.5 m
so the tree is 12.5 m high.

I know you got that numerical answer but I didn't like the way you made your statements
e.g.
1m = .4m makes no sense, 1m cannot be .4m

(I know this might seem petty, but to mathematicians this is just as grating as bad grammar is to an English teacher.)