At sea, the distance to the horizon is directly proportional to the square root of the elevation of the observer. If a person who is 36ft above the water can see 7.4mi, find how far a person 64ft above the water can see. Round to nearest tenth of a mile.

Solution:

S: the distance to the horizon

H: the elevation of the observer

S= k*(H)^0.5

7.4 mile = k* (36)^0.5

X mile= k* (64)^0.5

X= 9.87 mile

so a person 64ft above the water can see 9.9 miles.