The answer is steamboats! The first steamboat came year 1807 and was invented by John Fitch:)
 
        
             
        
        
        
Roughly 7! 7 x 48 is 336 which is two short so maybe just say 8 to be safe.
        
                    
             
        
        
        
Changes in the orbit of the earth caused the ice sheets to spread across Canada. 
        
             
        
        
        
Answer:

Explanation:
Angle of depression = 
b = Height of building = 42 feet

p = Distance from the car to the base of the building
From the trigonometric identities we get

The distance from the car to the base of the building is 
.