# Geometry

 The flashcards below were created by user Anonymous on FreezingBlue Flashcards. The sum of the angles in a triangle always equal? 180 The perimeter of a triangle is the sum of: the length of its sidesa+b+c = # (perimeter) Area of triangle formula? Base * Height / 2A = B*H/2 The height/altitude of a triangle is always perpendicular to the... base The longest side of a triangle is always the side... opposite the greatest angle The shortest side of a triangle is always the side... opposite the smallest angle Angles inside a Quadrilateral always add up to... 360 What are the 4 most common Quadrilaterals? 1) Square2) Rectangle3) Parallelogram4) Trapezoid Area of Square = L2 Perimeter of a square = 4L What am I? 1) All sides are same length and opposite sides are parralel 2) All angles = 90 Square What am I? 1) Opposite sides are parallel and the same length 2) All angles = 90 Rectangle What am I? 1) Opposite sides are parallel and the same length 2) Interior angles add up to 360 Parallelogram What am I? 1) Two sides are parallel 2) Interior angles add up to 360 Trapezoid Area of a Rectangle = L * W Perimeter of a Rectangle = 2L + 2W Area of a Parallelogram = Base * Height Perimeter of a Parallelogram = 2a + 2b Rhombus means... All sides are the same length, but the angles are not 90 degrees. Area of a Trapezoid = 1/2(b+c) * H Perimeter of a Trapezoid = a + b + c + d Radius Definition: Describes the distance from the center of the circle to the circle itself. Diameter Definition: Describes the distance from one side of the circle to the other side, intersecting the center. Also twice the length of the radius. Chord Definition: A line that connects any two points on a circle. Not necessarily through the center. Note the diameter is a chord. (pi) = 3.14 or 22/7 Area of a circle = r2 Circumference = 2 r or d(d=diameter) What direction are the quadrants labeled on the coordinate plane? Counterclockwise. Starting with 1 in upper right. All algebraic equations that are linear (no exponents) can be mapped on the coordinate plane as a straight line. With what equation? y = mx + b m = slopeb = y-intercept-b/m = x-intercept Slope = change in ychange in x Y2-Y1X2-X1 If the slope = pos value, line points... up to right If the slope = neg value, line points... down to right A right angle triangle is defined by what? And what calculation allows you to calculate the length of one side if you know the other two sides? Right angle triangle = has one angle equal to 90 deg Pythagorean Theorema2 + b2 = c2 What are the two most common values (or ratio of) used on the GMAT for right triangles & their side lengths? 3,4,5 or 5,12,13 Two other very common right triangles are? 30/60/90 & 45/45/90 30/60/90 Triangles always have sides in what proportions? 1, √3, 2 or x, x√3, 2x For any right triangle you need how many sides to solve for another side? Need 2 sides to solve for 1 In a 30/60/90 triangle 2x = short, med, or long side? And where is located? 2x = longest side & is always opposite the the 90 degree AuthorAnonymous ID89028 Card SetGeometry DescriptionGeometry Updated2011-06-04T05:10:14Z Show Answers