4.) What are 3 devices used to measure angles?

There are many devices used to measure angles. These include the following: clinometer, goniometer, magnetic compass, protractor, sextant, and theodolite. Each device will measure a different type of angle.

1.) A clinometer is a device used to measure an angle from a known horizontal distance. Foresters use these devices to measure the height of a tree by standing a known distance from the tree and measuring, from there, the angle to the top of the tree. Trigonometry follows this to determine the height given that distance and angle.

http://www.tkcs-collins.com/truman/rpn/rpn_clin.shtml

2.) A reflecting goniometer measures the angles on crystals. The theodolite goniometer, a crystal goniometer with 2 graduated circles arranged at right angles with one on top of the other, is responsible for allowing certain angular measurements in one section and, with the exception of the cemented surface, on all surfaces without moving the crystal.

http://chem.ch.huji.ac.il/~eugeniik/history/wollaston.html

3.) A magnetic compass is used to determine the direction in which you are facing while outside. The compass is divided from 0 degrees to 359 degrees clockwise. North is 0 degrees, East is 90 degrees, South is 180 degrees, and West is 270 degrees. This is used by hikers and explorers to determine which direction they are facing on Earth's surface.

http://www.cwu.edu/~nancyh/compass_tutorial.html

4.) A protractor is used to measure angles on a coordinate plane or another similar plane. This device will measure angles up to 180 degrees in size due to the shape and size of the protractor. This device is also used to draw angles as well.

http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=protractor

5.) A sextant is a device used to measure certain angular distances in navigation, observing altitudes of celestial bodies as in precise latitude and longitude.

http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=sextant

6.) A theodolite is used to measure horizontal and also vertical angles. This device is used mainly in the profession of surveying.

http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=theodolite