Answer:
Correct option: Third one: 213 mi
Step-by-step explanation:
The distance from the plane to the horizon is the segment EH in the figure.
The altitude of the plane is 30,000 feet, which is equal to 5.6818 miles, and that is the value of the segment ED.
The segment DC is equal segment CH, as they are the radius of the circle.
So know, to solve this problem, we can use Pythagoras' equation:
EC^2 = CH^2 + EH^2
(5.6818+4000)^2 = 4000^2 + EH^2
EH^2 = 4005.6818^2 - 4000^2
EH^2 = 45486.6828
EH = 213.2761 miles
Rounding to nearest mile, we have EH = 213 miles
Correct option: Third one.
