1. Quick direct variation problem

The distance $d$ to the visible horizon varies directly with the square root of the height $h$
of the observer above sea level. An observer 1.8 m tall can see 4.8 km out to sea when
standing on the shoreline.

I know how to do it but the answers says I'm wrong...

$d \alpha \sqrt{h}$ <--- this is meant to be proportional sign but I can't seem to find it and alpha looks close enough xD

so $d=k*\sqrt{h}$

$4.8=k*\sqrt{1.8}$

k=3.57771

we found k then:

$d=k*\sqrt{4}$

$d=3.57771 * 2$

but the answer is like 8. something

2. Part of the question appears to be missing.