GEOMETRY Flashcards
Volume of a cylinder
Pi r^2 h
Volume of a cylinder: multiplying r and h
Pi x (2r)^2 x 2h
= pi x 4 x r^2 x 2 x h
= 8 pi r^2 h
Sum of all interior angles in a triangle =
180 degrees
Perimeter of triangle =
Sum of all sides
Area of a triangle =
(1/2)(base)(height)
Base and Height of a triangle must ….
Be perpendicular / form a 90 degree angle
Triangle Inequality Theorem
- Any side of a triangle is always shorter than the sum of the other two sides
- Any side of a triangle is always longer than the difference of the other two sides
Isosceles Triangle is…
A triangle in which two sides are equal (so their angles are also equal)
Equilateral triangle
All three sides (and all three angles) are equal
Right Triangle - Pythagorean Theorem
A^2 + b^2 = c^2
THE SQUARE OF THE HYPOTENUSE OF A RIGHT TRIANGLE IS EQUAL TO THE SUM OF THE SQUARE OF THE TWO ADJACENT SIDES
3 x 4 x 5 triangle
5 x 12 x 13 triangle
If you see a right triangle with sides of 3, 4; 4,5; 3,5 (or a multiple of these numbers), you know the other side is one of (a multiple of) 3, 4 or 5
SAME WITH 5 X 12 X 13
ONLY APPLIES TO RIGHT TRIANGLES
45 45 90 TRIANGLE
A right triangle with a 45 degree angle is an isosceles right triangle with one other 45 degree angle
Sides other than the hypotenuse will be equal to x
The hypotenuse will be equal to x root 2
30 60 90 triangle
60 / 30 / 90 degrees
Side opposite 30 degrees is x
Hypotenuse is 2x
Other side is x root 3
Area of a circle
Pi r squared
Circumference of a circle
2 pi r
