Maths formulas

(pi = = 3.141592...) Area Formulas                                                                                       Note: "ab" means "a" multiplied by "b". "a2" means "a squared", which is the same as "a" times "a". Be careful!! Units count. Use the same units for all measurements. Examples square = a 2 rectangle = ab parallelogram = bh trapezoid = h/2 (b1 + b2) circle = pi r 2 ellipse = pi r1 r2   triangle = one half times the base length times the height of the triangle    equilateral triangle = triangle given SAS (two sides and the opposite angle)= (1/2) a b sin C triangle given a,b,c = [s(s-a)(s-b)(s-c)] when s = (a+b+c)/2 (Heron's formula) regular polygon = (1/2) n sin(360°/n) S2    when n = # of sides and S = length from center to a corner   Units Area is measured in "square" units. The area of a figure is the number of squares required to cover it completely, like tiles on a floor. Area of a square = side times side. Since each side of a square is the same, it can simply be the length of one side squared. If a square has one side of 4 inches, the area would be 4 inches times 4 inches, or 16 square inches. (Square inches can also be written in2.) Be sure to use the same units for all measurements. You cannot multiply feet times inches, it doesn't make a square measurement. The area of a rectangle is the length on the side times the width. If the width is 4 inches and the length is 6 feet, what is the area? NOT CORRECT .... 4 times 6 = 24 CORRECT.... 4 inches is the same as 1/3 feet. Area is 1/3 feet times 6 feet = 2 square feet. (or 2 sq. ft., or 2 ft2).   trignometry Table                                                                                 Trig Table of Common Angles angle (degrees)  0  30  45  60  90  120  135  150  180  210  225  240  270  300  315  330  360 = 0 angle (radians)  0  PI/6 PI/4 PI/3 PI/2 2/3PI 3/4PI 5/6PI PI  7/6PI  5/4PI  4/3PI  3/2PI  5/3PI  7/4PI  11/6PI  2PI = 0 sin(a) (0/4) (1/4) (2/4) (3/4) (4/4) (3/4) (2/4) (1/4) (0/4) -(1/4) -(2/4) -(3/4) -(4/4) -(3/4) -(2/4) -(1/4) (0/4) COs(a) (4/4) (3/4) (2/4) (1/4) (0/4) -(1/4) -(2/4) -(3/4) -(4/4) -(3/4) -(2/4) -(1/4) (0/4) (1/4) (2/4) (3/4) (4/4) tan(a) (0/4) (1/3) (2/2) (3/1) (4/0) -(3/1) -(2/2) -(1/3) -(0/4) (1/3) (2/2) (3/1) (4/0) -(3/1) -(2/2) -(1/3) (0/4) Those with a zero in the denominator are undefined. They are included solely to demonstrate the pattern.  Math.com