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Clinometer (forestry)
From Wikipedia, the free encyclopedia

A clinometer used in forestry
The clinometer, known in many fields as an inclinometer, is a common tool used in forestry to measure slope, vertical angles, and – in combination with distance measurements – elevation change or tree heights. Contents [hide] * 1 How it works * 2 Units of measure * 3 Tree height measurement * 4 Slope measurement * 5 Manufacturers * 6 See also * 7 References| -------------------------------------------------

[edit]How it works
A forester using a clinometer makes use of basic trigonometry. First the observer measures a straight-line distance D from some observation point O to the object. Then, using the clinometer, the observer measures the angle a between O and the top of the object. Then the observer does the same for the angle b between O and the bottom of the object. Multiplying D by the tangent of a gives the height of the object above the observer, and by the tangent of b the depth of the object below the observer. Adding the two of course gives the total height (H) of the object, in the same units as D.[1] Note that since multiplication is distributive it is equally valid to add the tangents of the angles and then multiply them by D: A = tan a

B = tan b
H = (A × D) + (B × D) = (A + B) × D
Note also that both angles should be positive numbers (i.e. ignore any minus sign on the clinometer's scale). -------------------------------------------------
[edit]Units of measure
There are typically three different units of measure that can be marked on a clinometer: degrees, percent, and topo. When buying a clinometer it is important to make sure it is calibrated to units suitable for the intended use. -------------------------------------------------

[edit]Tree height measurement
[[Image:Illustration of the basic trigonometric principles used by a clinometer.JPG|right|200px|thumb|Tree height...

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History
Main article: Wrestling history
Wrestling is one of the oldest forms of combat with references to it as early as the Iliad, in which Homer recounts the Trojan War in the 13th or 12th century BC.[3] The origins of wrestling can be traced back 15,000 years through cave drawings in France. Babylonian and Egyptian relief's show wrestlers using most of the holds known to the present-day sport. In ancient Greece, wrestling occupied a...

...height of the height of something that we cannot measure directly. In this case, it is seldom practical to measure the height the highest point of our school with a tape measure, but it can be accomplished easily by using an instrument called a clinometer to measure the angle of sight between the observer, in this case, Shanthanu, a somewhat normal human being, who holds a height of 1.72m, and the highest point of the school, and a measure tape to identify the distance of the...