Geometry Flashcards
What do the exterior angles of a triangle add to?
360
What do the interior angles of a triangle add to?
180 Degrees
What is the area of a triangle formula?
Area = (1/2)(B)(H)
What is the Pythagorean theorem?
A^2 + B^2 = C^2
What is an equilateral triangle?
All sides are equal. All angles = 60 degrees. When an equilateral triangle has an angel bisected it becomes a 30/60/90 triangle.
What is an isosceles triangle?
Two sides are equal and two angles are equal
What is area of a circle?
Area = (pie)(r^2)
What is the circumference of a circle?
Circumference = (pie)(D) = 2(pie)(r)
What do you need to find the arc-length or arc degree of a circle?
The degree of an arc/360 is proportional to the area and circumference of a circle
What is the relationship between a radius and a diameter?
(2)(radius) = diameter
What are the total degrees in a circle?
360
What is the volume of a rectangular solid?
Base times height
What do two angles on a line equal?
180 degrees
What do angles around an intersection of at least two lines add to?
360 Degrees
Do parallel lines ever cross?
Not on a 2D plane. Not if they are on the same plane.
If a triangle is inscribed inside a circle so that one side of the triangle is a diameter. What type of triangle is it?
A right triangle.
If given a radius of a circle what can you determine?
Circumference, diameter, area. All other necessary values on the GMAT
What is a tangent line?
A line that touches a circle on exactly one point. It’s perpendicular to the radius at the point if tangency.
What axis is vertical?
Y axis
What axis is horizontal
X axis
What is the slope formula?
Rise/Run - (Y1 - Y2)/(x2 - x1) - (Delta Y / Delta X)
How are points written?
(X, Y)
What is the line formula?
Y = mx + b
M is slope
B is y intercept
(X,y) is a point on the line
What is the theory of triangle sides?
Two sides added together are always longer than the third side. The difference of any two sides is less than the third side.
Area if a rhombus?
A = (b)(h)
Area of a trapezoid?
A = (1/2)(b1 + b2)(h)
What is pie?
Circumference/Diameter. Infinite # 22/7 is close. 3.14 is also close.
What is 0/x =
Zero slope/Horizontal line
What is a 0 slope look like?
A horizontal Line
What does an undefined slope look like?
Vertical line. X/0
What is the slope of a vertical line?
Undefined/No Slope - Cannot divide anything by 0. (X/0 = Undefined)
Name two unique degree combinations in right triangles and the corresponding sides.
45: 45:90 X:X:Xsq.2
30: 60:90. X:Xsq3:2X
What are the two common Pythagorean triples?
3: 4:5
5: 12:13
x:12:13
5:12:13
5:x:13
5:12:13
5:12:x
5:12:13
What happens when you draw a diagonal in a parallelogram?
You bisect the area and if you have two lines they bisect each other
Def: Paraelleogram
Closed quadrilateral with two sets of parallel lines. Rectangles, squares, rhombus.
Volume of a rectangular solid?
V = (l)(w)(h)