<PRE><B>Question 799682</B>
1. Due to the curvature of the earth, the maximum distance D that you can see from the top of a tall building or from an airplane at height h is given by the function:
D(h) = {{{sqrt(2rh+h^2)}}}
where r =3960 mi is the radius of the earth and 
D and h are measured in miles.
:
a. How far can you see from the observation deck of Toronto’s CN Tower,
1135 ft above the ground?
d = {{{1135/5280}}} = .2145 mi
D(h) = {{{sqrt((2*3960*.2145)+.2145^2)}}}
D(h) = 41.2 mi
: 
b. Commercial aircraft fly at an altitude of about 7 mi.
 How far can the pilot see?
D(h) = {{{sqrt((2*3960*7)+.7^2)}}}
D(h) = 235.56 mi</PRE>