Comments on: What would be the best way to measure a flag pole using only a protractor and reference object? ? http://www.usedfiretrucksforsale.net/what-would-be-the-best-way-to-measure-a-flag-pole-using-only-a-protractor-and-reference-object.html Old, Used & Antique Fire Trucks, Enginges & Apparatus Wed, 10 Mar 2010 13:11:46 -0700 http://wordpress.org/?v=2.8.2 hourly 1 By: Captain Mephisto http://www.usedfiretrucksforsale.net/what-would-be-the-best-way-to-measure-a-flag-pole-using-only-a-protractor-and-reference-object.html/comment-page-1#comment-1522 Captain Mephisto Sat, 07 Nov 2009 08:14:52 +0000 http://www.usedfiretrucksforsale.net/what-would-be-the-best-way-to-measure-a-flag-pole-using-only-a-protractor-and-reference-object.html#comment-1522 Your reference object should be within sight of the flagpole on level ground. Assuming this to be the case do the following: 1. go to the base of the flagpole and measure the angle from the ground to the top of the reference object. Call this angle R. 2. go to the reference object and do the same as in 1 with respect to the top of the flagpole. Call this angle P. 3. Using the following conventions: D = distance between reference object and flagpole (unknown) H = height of reference object (known) F = height of flagpole (to be determined) R and P are defined above. We can write: tan(R) = H/D and tan(P) = F/D Solve each for D: D = H/tan(R) and D = F/tan(P) Now equate the Ds: H/tan(R) = F/tan(P) F = H*[tan(P)/tan(R)] Since you know H, P and R you can easily calculate F Your reference object should be within sight of the flagpole on level ground. Assuming this to be the case do the following:

1. go to the base of the flagpole and measure the angle from the ground to the top of the reference object. Call this angle R.

2. go to the reference object and do the same as in 1 with respect to the top of the flagpole. Call this angle P.

3. Using the following conventions:
D = distance between reference object and flagpole (unknown)
H = height of reference object (known)
F = height of flagpole (to be determined)
R and P are defined above.

We can write:
tan(R) = H/D and tan(P) = F/D

Solve each for D:
D = H/tan(R) and D = F/tan(P)

Now equate the Ds:
H/tan(R) = F/tan(P)
F = H*[tan(P)/tan(R)]

Since you know H, P and R you can easily calculate F

]]> By: Paschal H http://www.usedfiretrucksforsale.net/what-would-be-the-best-way-to-measure-a-flag-pole-using-only-a-protractor-and-reference-object.html/comment-page-1#comment-1523 Paschal H Sat, 07 Nov 2009 08:14:52 +0000 http://www.usedfiretrucksforsale.net/what-would-be-the-best-way-to-measure-a-flag-pole-using-only-a-protractor-and-reference-object.html#comment-1523 I think you need to be able to measure a distance on the ground from the flag pole to the reference object. Now if you know that distance, you can site with the protractor to find the angle that lines up the top of the reference object to the top of the flag pole. F = Flag Pole Height R = Refenence Height X = Distance from flag pole to reference A = angle measured Tan(A) = (F-R) / X Solve for F. I think you need to be able to measure a distance on the ground from the flag pole to the reference object.

Now if you know that distance, you can site with the protractor to find the angle that lines up the top of the reference object to the top of the flag pole.

F = Flag Pole Height
R = Refenence Height
X = Distance from flag pole to reference
A = angle measured

Tan(A) = (F-R) / X

Solve for F.

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