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- Use the fact that the earth is is 3960 miles and 1 mile is 5280 feet answer the following question.
A tower of a submarine is approximately 18 feet above sea level. How far can a person see from the top of the tower?
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1. Make a sketch. Draw a circle. It will represent the Earth (a section).
Draw the radius. The radius of the circle is R = 3960 miles.
Proceed it outside by the value of 18 feet = = 0.00341 miles
( 1 mile = 5280 feet). It represents "the tower".
Draw the tangent line to the circle "from the top of the tower".
You want to know the length of this tangent segment.
2. Do you see a right angled triangle in your plot ?
The tangent segment is the leg of this right-angled triangle, and its length is
.
3. Calculate. It will be your answer.
If you have questions, send them to me through the "Thank you" notes/window.
If you do, do not forget to place the ID number of this problem (# 1066309).
For your information, you have this free of charge online textbook on Geometry
GEOMETRY - YOUR ONLINE TEXTBOOK
in this site.
The part if this textbook relevant to this problem is the section "Properties of circles, inscribed angles, chords, secants and tangents".