003 FOM - Geometry Flashcards
What are vertical angles? What is true about them?
Opposite angles created when two straight lines intersect. They have the same measure.
Define a right angle.
An angle with the measure of 90 degrees.
How is a perpendicular line denoted?
By an upside down T.
Define a polygon.
A closed plane figure formed by three or more line segments (each a “side” of the polygon).
Define vertices.
The points of intersection on a polygon.
Define convex polygon.
Polygon where each interior angle has a measure of less than 180 degrees.
Define a quadrilateral
Polygon with four sides
Define a pentagon.
Polygon with five sides.
Define hexagon
Polygon with six sides.
Express the sum of the interior angles of a polygon as an equation.
180 degrees x (n-2)
Where n is the number of sides of the polygon.
Define isosceles triangle.
At least two sides of the triangle are of equal length.
What is true about sides/angles in an isosceles triangle?
If two sides are the same length, their opposite angles are the same length (and vice versa).
What are the components of a right triangle?
Sides forming right angle are LEGS. Third side opposite the right angle (and the longest side) is the HYPOTENUSE.
Define Pythagorean theorem.
In a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the legs.
Define right triangle
A triangle that has a right angle. Also any triangle in which the lengths of the sides are in the ratio 3:4:5.
What is the altitude of a triangle?
The segment drawn from a vertex perpendicular to the side opposite that vertex.
What is the base of a triangle?
Relative to a vertex and an altitude, the opposite side (ie the side where the altitude connects to). Any side of a triangle can serve as a base (whatever side the height is perpendicular to).
What is the area of a triangle?
(length of altitude * length of the base) / 2
aka, the average of the altitude and base
OR 1/2(base*height)
What is the ratio of sides in a 45-45-90 degree triangle?
1:1: sq root 2
In triangle JKL with hypotenuse KL, if JL =2 and JK = 2, then KL = 2sq rt 2
What is the ratio of sides in a 30-60-90 triangle?
1: sq rt 3: 2
For triangle XYZ with hypotenuse YZ, if XZ = 3, then XY = 3sqrt3 and YZ = 2X3=6
Define a line segment
A part of a line (i.e., a straight line that extends without end in both directions) between two endpoints on the line.
Define quadrilateral
Polygon with four sides
Define parallelogram
Quadrilateral in which both pairs of opposite sides are parallel and equal.
Define rectangle vs. square
Parallelogram with right angles. Square is a rectangle with all sides of equal length.
Define trapezoid
Quadrilateral with two sides parallel. Third and fourth sides are slightly diagonal.
What is the area of a trapezoid?
(1/2)(sum of the lengths of the bases)(the height)
Define a circle
Set of points in a plane that are located the same distance from a fixed point (the center of the circle).
Define chord in the context of a circle.
Line segment that has its endpoints on the circle.
Define diameter.
A chord that passes through the center of the circle.
Define radius
Segment from the center of the circle to a point on the circle. Equals one-half of the diameter.