Jaden Nichols the first part of the word is from Greek trigon "triangle". The second part of trigonometry is from Greek metron "a measure.“ The Indo-European root is me- "to measure.“ Trigonometry is literally the measuring (of angles and sides) of triangles. Trigonometry defines relations between elements of a triangle. It is a branch of geometry. http://www.cut-the-knot.org/WhatIs/WhatIsTrigonometry.shtml It came from Ancient Egyptian and Babylonian times as a way to work with triangles. Trigonometry emerged as a way to work with triangles and circles in the 15th century. http://www.cut-the-knot.org/WhatIs/WhatIsTrigonometry.shtml It took more than one mathematician to discover trigonometry. Hipparchus-trig table that measured length for angles Ptolemy-table increasing chords by 1 degree Indian mathematicians-sine functions rather than chords Muslim astronomers-studies by the Greeks and Indians http://www.trigonometry-help.net/history-of-trigonometry.php Civil Engineering-calculating surfaces and shapes Sailors-navigation, determining position Astronomy-the locations and shapes of the planets Electronic fields-quick calculating with math and science Carpenters-building, shaping 3 most used functions and their ratios: Sine=opposite/hypotenuse Cosine=adjacent/hypotenuse Tangent=opposite/adjacent Other 3 functions and their ratios: Cosecant=hypotenuse/opposite Secant=hypotenuse/adjacent Cotangent=adjacent/opposite Yes, they are related. Reciprocal functions! http://www.regentsprep.org/Regents/math/algtrig/ATT1/trigsix.htm http://www.regentsprep.org/Regent s/math/algtrig/ATT1/trigsix.htm This was the best website I found. It shows the functions and their ratios. It also shows their relations and other things. It isn’t plain looking and it was kid-friendly! A circle with a radius of 1 with its center at 0. Because the radius is 1, it is easy to measure sine, cosine, and tangent. They are related. They are used in trig, can be measured in similar ways. Scoring a goal in soccer is done with a variety of different shot positions, but each position involves knowing the length and depth of the goal. The distance from the goal, diameter of the soccer ball and height of the goal form a variety of angles demonstrating triangular scoring patterns in soccer. We could study and make a chart or graph about the different angles and shot positions. http://www.ehow.com/list_5939810_high-school-trigonometry-project-ideas.html