There are numerous ways to find the height of a flagpole.
1. Cut it down and measure it. (Don't forget to measure the stump.)
2. Measure its shadow. At the same time, measure the length of the shadow of an object whose height you know. Set up a proportion relating the height of each object to its shadow length, and solve for the height of the flagpole.
3. Tie a string to the top flag snap hook and raise it up. Measure the amount of string, making allowances as necessary for the height of the top above the highest point the string can be raised to.
4. Ask someone who knows.
5. Look at the site plans.
6. Stand some distance from the pole and measure the height as it appears at arm's length. Rotate your arm so that distance can be measured along the ground from the base of the flagpole.
7. At some known distance from the flagpole, determine the angle of a line of sight to the top. (Surveying or navigation instruments are good for this.) You may have to determine the height of the instrument as well.
8. Throw a rock as high as the flagpole and time its descent to earth. Compute the height based on the acceleration due to gravity.
9. Time how long it takes for the shadow of the top of the flagpole to move a given distance. Based on the track of the sun through the sky on the day and time of your measurement, you can compute the height of the pole.
When I've tried to do suggestions 2 and 6, I found that suggestion 6 is easier by far. I expect suggestion 7 would work well, too. It turns out that the shadow of the top of a flagpole is not very distinct, so it is hard to measure--a problem that plagues suggestion 9 as well.
1. Cut it down and measure it. (Don't forget to measure the stump.)
2. Measure its shadow. At the same time, measure the length of the shadow of an object whose height you know. Set up a proportion relating the height of each object to its shadow length, and solve for the height of the flagpole.
3. Tie a string to the top flag snap hook and raise it up. Measure the amount of string, making allowances as necessary for the height of the top above the highest point the string can be raised to.
4. Ask someone who knows.
5. Look at the site plans.
6. Stand some distance from the pole and measure the height as it appears at arm's length. Rotate your arm so that distance can be measured along the ground from the base of the flagpole.
7. At some known distance from the flagpole, determine the angle of a line of sight to the top. (Surveying or navigation instruments are good for this.) You may have to determine the height of the instrument as well.
8. Throw a rock as high as the flagpole and time its descent to earth. Compute the height based on the acceleration due to gravity.
9. Time how long it takes for the shadow of the top of the flagpole to move a given distance. Based on the track of the sun through the sky on the day and time of your measurement, you can compute the height of the pole.
When I've tried to do suggestions 2 and 6, I found that suggestion 6 is easier by far. I expect suggestion 7 would work well, too. It turns out that the shadow of the top of a flagpole is not very distinct, so it is hard to measure--a problem that plagues suggestion 9 as well.
