at height of h meters you can see V kilometers to the horizon. These numbers are related by the equation V=3.5sqrt h. A person can see 278 km to the horizon from an airplane window. How high is the airplane?

Question

at height of h meters you can see V kilometers to the horizon. These numbers are related by the equation V=3.5sqrt h.  A person can see 278 km to the horizon from an airplane window. How high is the airplane?

anonymous · Answer

It's just
$$278=3.5\sqrt{h}$$
I hope you can solve it afterwards?

anonymous · Answer

yeah i have no idea lol thats why im here

anonymous · Answer

crap its 378 not 278

anonymous · Answer

$$278=\frac{7}{2}\sqrt{h}$$
multiply both sides by 2 and divide by 7
$$\frac{556}{7}=\sqrt{h}$$
and square it
$$h=\frac{309136}{49}\approx6308m\approx6.3km$$