I

I - Interior Angles: the inside angles of a polygon or two parallel lines.



link:http://www.mathwarehouse.com/geometry/triangles/-scroll down to the one that says"Interactive Demonatration of Interior Angle Sums" **Interior angle measures in regular polygons** The interior angle equation is... 180(n-2) where n= the number of sides of the shape
 * name ||  || number of sides ||   || sum of interior angles ||   || interior angle ||
 * triangle ||  || 3 ||   || 180 ||   || 60 ||
 * square ||^  || 4 ||^   || 360 ||^   || 90 ||
 * pentagon ||^  || 5 ||^   || 540 ||^   || 108 ||
 * hexagon ||^  || 6 ||^   || 720 ||^   || 120 ||
 * heptagon ||^  || 7 ||^   || 900 ||^   || 128 4/7 ||
 * octagon ||^  || 8 ||^   || 1080 ||^   || 135 ||
 * nonagon ||^  || 9 ||^   || 1260 ||^   || 140 ||
 * decagon ||^  || 10 ||^   || 1440 ||^   || 144 ||
 * undecagon ||^  || 11 ||^   || 1800 ||^   || 150 ||
 * dodecagon ||^  || 12 ||^   || 2340 ||^   || 156 ||
 * n-gon ||^  || n ||^   || 180(n-2) ||^   || 180(n-2)/n ||
 * n-gon ||^  || n ||^   || 180(n-2) ||^   || 180(n-2)/n ||
 * n-gon ||^  || n ||^   || 180(n-2) ||^   || 180(n-2)/n ||

Isosceles Triangle - a triangle that has at least two sides that are the same length



====Irrational number. An irrational number is any number that can be expressed as a fraction. An example of this is pi. ====

__//** Integers - numbers consisting only of negitive and positive numbers together! An example is ... -5, -4, -3, -2, -1, 0, 1,2,3,4,5... **//__

=__The imaginary number I__ i is an imaginary number that, when squared, equals -1 the equation for the imaginary number I is I*I=-1. =  I is for inverse operations. Inverse Operations are pairs of operations that undo each other. Examples: Addition and subtraction are inverse operations. Multiplication and division are inverse operations.



INTERQUARTILE RANGE: The interquartile range is the range of the middle half of the data.

I is for interest. Interest is the amount of money earned or paid for the use of it.

I can also be 'is'. In a word problem, 'is' means equal to, just like 'the product of x and y' means to multiply x and y.