Answer: 15
Step-by-step explanation: Label the tree with 4m for the height of the tree and the base of the triangle 15m for the shadow it cast. The angle is adjacent to 15m and opposite to 4m making the equation you use tanx=4/15 which when you solve becomes tan^-1(4/15) which gives you 15.
I think it is B (don't take me for certain cuz I don't know)
(-1,-2) = (-5,2), (-1,0)=(-5,4) , (3,-3) =(-1,1) this might be wrong
Inverse relationships are of the form xy=k or if you prefer y=k/x so to find the constant we can say:
18(0.25)=k=4.5
So you could say: IR=4.5 or I=4.5/R