Plane Geometry Flashcards
When starting a geometry problem, always…
Write all given info on the picture (or draw your own) and write down any formulas you need/have
All lines form an angle of…
180 degrees
If a line is cut by another line…
It divides that 180 degrees into two pieces that add up to 180 degrees
Above and below a line…
There is 180 degrees
Opposite, or vertical angles, are always -blank-
Equal
A 3-sided figure whose angles always add up to 180 degrees is a…
Triangle
The largest angle on a triangle is always…
Opposite the largest side
A triangle with one 90 degree angle
Right triangle
The longest side of a right triangle is the -blank-
Hypotenuse
The three common right triangle proportions are:
(3-4-5) (5-12-13) (7-24-24) and their multiples
An isosceles right triangle is always in a particular proportion. The hypotenuse is always one of the other sides times…
The root of two
Whatever the proportions of a 30-60-90 triangle, the hypotenuse…
Is always two times as large as the adjacent
In a 30-60-90 triangle, the medium side is always…
The short side times the root of 3
When two triangles are proportionate, you can find the missing side with a proportion equation:
Short leg/hypotenuse
Triangles are similar if…
Their angles have the same measures
