Flashcards in Part 3: Geometry Deck (39)
What is the equation to calculate the number of degrees in a polygon?
degrees = (n+2)*180, where n is the number of sides.
What is the pythagorean theorem?
a^2 + b^2 = c^2, used to determine length of sides in a triangle with one right angle (a right triangle).
What is an equilateral triangle?
a triangle where all three sides are the same length (congruent).
What is an isosceles triangle?
a triangle where two sides are congruent.
What are the ratio of sides in an isosceles right triangle?
a to a√2
What are the ratio of sides in an 30-60-90 triangle?
2a to a√3 to a
What is the area of a triangle?
(bh)/2, which is base times height divided by 2.
What makes for congruent triangles?
All sides are the same. Or one side and two angels are the same. Or one angle and two sides are the same.
What makes for similar triangles?
All three angles are the same.
What is the area of a quadrilateral?
A = bh
What is the area of a trapezoid?
A = 1/2(b1 + b2)h
In a circle, what is a chord?
A line segment whose end points touch a circle's circumference.
How to determine the length of an arc?
Given the angle of the arc, the length of the arc can be calculated with the following ratio:
arc angle/360 = arc length/circumference
What is the area of a circle?
What is the area of a sector?
Given the angle of the arc of the sector, the area can be calculated using the following ratio:
area of sector/area of circle = sector angle/360
What is special about an inscribed triangle and it's angle (or side)?
If one of the sides is the diameter of the circle, then it is a right triangle. If one of the angles of an inscribed triangle is 90 degrees, than one of its sides if the diameter.
How is a polygon circumscribe a circle?
If all sides of the polygon are tangential, then it circumscribes the circle.
What are concentric circles?
Circles that share the same center point.
what is the volume of a rectangular solid?
V = lwh
What is the surface area of a rectangular solid?
A = 2(lw + wh + hl)
What is the a circular cylinder?
Is a can but where the circles can be slid on their respective planes in any direction.
What is a right circular cylinder.
What is an axis in a circular cylinder?
It is the line connecting the center of both circles in a cylinder.
What is the volume of a can?
V = πr^2h
What is the surface area of a can?
A = 2πr^2 + 2πrh
Given two parallel lines and two intersecting lines, one of the angles is 57 degrees and the other is 42. What are x and y.
x is also 57 degrees. y is 180-42, which is 138 degrees.
Given an isosceles triangle, and an outside angle of 125 degrees, what are x and y?
y is 125 degrees. x is 180 - 55 - 55 = 70 degrees.
Given two inside angles x and y and one outside angle z, what is their relationship to each other?
x + y = z
What is the sum of the interior angles inside a decagon?
8*180 = 1440 degrees