Geometry Flashcards
To what do three angles in a triangle add up?
180 degrees
Most commonly used right triangle triples? (a^2+b^2=c^2 triples)
3-4-5 (and its multiples)
5-12-13 (and its multiples)
7-24-25 (and its multiples)
What is the hypotenuse of an isosceles right triangle?
X(square root of 2)
When X= length of AN equal side
In a 30-60-90 (degrees) triangle how long is the hypotenuse?
It is always double the shortest side.
In a 30-60-90 (degrees) triangle how long is the medium side?
X(square root of 3)
When X=length of the shortest side.
What is the area formula for a triangle?
Area= (base x height)/2
How do you solve a similar triangle equation?
You set up a proportion equation.
What do the degrees of interior angels of a quadrilateral add up to?
360 degrees
How many angles do parallelograms have in reality?
Two
What is the area formula for a trapezoid?
1/2(base 1 + base 2)(height)
(The average of two parallel sides x the height)
What is the formula for the area of a circle?
Pi(r^2)
What is the formula for the circumference of a circle?
2pi(r)
How long is diameter?
Twice the radius.
What is the difference between an equilateral, isosceles, and non-equal triangles?
All sides are equal, two sides are equal and no sides are equal.
Which angles are supplementary in a parallelogram?
Adjacent angles
What is the first step of subtracting an angle from a circle?
Divide the angle by 360
Pythagorean theorem
a^2+b^2=c^2
Sum of angles in an n-sided polygon?
(n-2)180 degrees
Angle measures in a regular n-sided polygon?
[(n-2)180]/n
What is the arc of a circle?
A part of the circumference.
Bisect
To cut in half
Chord
Any line connecting two points on the edge of a circle
What is the name of the longest chord?
Diameter
Circumscribed
Surrounded by a circle as small as possible
Collinear
Lying in the same line
Congruent
Equal in size
Diagonal of a polygon
A line segment connecting two opposite vertices
Inscribed (angle in a triangle)
An angle in a circle with its vertex on the circumference
Perpendicular
At a 90 degree angle
Plane
A flat surface extending in all directions
Polygon
A closed figure with 2 or more sides
Regular polygon
A figure with all equal sides and angles
Sector
Any part of the area formed by two radii and the outside of the circle
Similar
Equal angles and proportional sides
Surface area
The sum of areas of each face of a figure
Tangent
Intersecting at 1 point
Vertex or vertices
A corner point. For angles, it’s where two rays meet. For figures, it’s where two adjacent sides meet
