2.  “Trigonometry is a branch of mathematics that developed from simple mensuration (measurement of geometric quantities), geometry, and surveying. In its modern form it makes use of concepts from algebra and analysis. Initially it involved the mathematics of practical problems, such as construction and land measurement; it has since been extended to the geometry of three-dimensional spaces in the form of SPHERICAL TRIGONOMETRY. “

3.  In Ancient Greece trough the studies of Hipparchus of Bithynia (190-120 B.C).  Trigonometric ratios was use for calculation of a planet’s positoin.

4.  There was more than one person responsible for the discovery of trigonometry.  Hipparchus, Abul Wafa, Aryabhata, Omar Khayyam, Bartholemaeus Pitiscus. There are many more.

5.  Astronomy- the foundations of trigonometry determines information on cellar bodies, mass, distances, orbits and speed.  Geography- the ability to help find the spherical- shape planet to make it critical. (global navigation and sonar)  Architecture- allows them to use measurements and angles so that blueprints can be created with raw materials  Physics- microwaves, radios and electromagnetic waves is used to measure and graph trigonometric functions. (sine and cosine)

6.  http://www.homeschoolmath.net/online /trigonometry.php http://www.homeschoolmath.net/online /trigonometry.php

8.  A unit circle is just a circle with the radius of 1.  A unit circle is seldom use in the simple geometry sense.  “Two triangles in a circle are similar if two pairs of angles have the same intercepted arc. Sharing an intercepted arc means the inscribed angles are congruent.”

9.  http://omega.albany.edu:8008/mat112d ir/trig.html http://omega.albany.edu:8008/mat112d ir/trig.html  http://www.slideshare.net/doozer_k/histo ry-of-trigonometry http://www.slideshare.net/doozer_k/histo ry-of-trigonometry  http://www.ehow.com/info_10052141_a pplications-trigonometry.html http://www.ehow.com/info_10052141_a pplications-trigonometry.html  http://www.brightstorm.com/math/geo metry/similarity/similar-triangles-in-circles- and-right-triangles/ http://www.brightstorm.com/math/geo metry/similarity/similar-triangles-in-circles- and-right-triangles/