**This Project is contributed by Mohammad Wasif X F**Introduction WHAT IS TRIGONOMETRY? THE WORD TRIGONOMETRY IS DERIVED FROM THE GREEK WORDS: I)TRIGONO AND 2)METRON.THE WORD TRIGONON MEANS A TRIANGLE AND THE WORD METRON MEANS A MEASURE.HENCE TRIGONOMETRY MEANS THE SCIENCE OF MEASURING TRIANGLES. Line of sight:- is the line drawn from the eye of an observer to the point in the object viewed by the observer. Angle of depression:-of a point on the object being viewed is the angle formed by the line of sight with the horizontal when the point is below the horizontal level. Angle of elevation:-of a point viewed is the angle formed by the line of sight with the horizontal when the point being viewed above the horizontal level. A clinometer is an instrument that measures vertical slope, usually the angle between the ground or the observer and a tall object, such as a tree or building.

**Aim :-**TO MAKE A CLINOMETER

**Material Required :**1-Protactor 2-Straw 3-Stone 4-Thread

**Procedure**Step 1 Get a protractor with one straight edge (a 180 degree protractor). Step 2 Tape a straw along the straight edge of the protractor. Step 3. Tie a string through the small hole on the straight edge that is directly across from the 0 degree mark on the protractor. This may also be labelled as 90 degrees. If your protractor does not have a small hole here, or if the hole is not situated correctly (this is a common problem with some cheap protractors), tape or glue the string to the protractor at this mark. Make sure the string dangles a few inches below the protractor. Step 4 Attach a washer or fishing weight to the dangling end of the string. Step 5 Sight the top of a tall object through the straw. Step 6 Note the number where the string crosses. Subtract this number from 90 to determine the angle of elevation between your eye and the top of the object you are sighting In the above case I measured the angle of elevation and observed that the angle is 36 degrees. According to the above rule I will have to subtract the measured angle with 90 degrees. So the angle of elevation is 90 degrees -36 degrees = 54 degrees.

**Conclusion:**From the above discussion we have seen that we can easily find out the heights and distances without any actual measurement. We used only clinometers to measure the angle of elevation & angle of depression. with the help of trigonometric formulae's we can easily find out the height and distances. Astronomers can easily find the distance of stars from earth with help of trigonometric formulae's.

**Resources:**Planet infinity. Mathematics Encyclopedia.

*I would like to congratulate Mohammad on behalf of Planet Infinity for doing such a wonderful job.*

## 4 comments:

Excellent work! The instructions and photographs are much better than the others I have found online. I am having my university students make clinometers for measuring the height of trees. :-)

An excellent article for me to adapt - I have 44 13yr olds making clinometers as an introduction to TAN taking them beyond basic Pythag. Also the other articles on this sight are excellent taking maths from the purely theoretical to the practical.

this article is very helpful every step is picturized so well that any student will be able to do it with much ease and fun

This article has helped me a lot. good work.thanks

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