Geometry Regents Review Flashcards
Sum of Interior Angles
180 (n - 2)
Each Interior Angle of a Regular Polygon
(180(n-2))/n
Sum of Exterior Angles
360
Each Exterior Angle
360/n
Midsegment on a Triangle:
- What is it?
- Relationship to the third side?
- What does it do to the triangle?
- A segment joining the midpoints
- 1/2 the length of the third side
- Splits the triangle into two similar triangles
Standard Form of a Line
y=mx+b
Slope Formula
m=(y2-y1)/(x2-x1)
Parallel Lines
same slope, different y-intercepts
Perpendicular Lines
negative reciprocal slopes
Collinear Points
same line
Midpoint Formula
M = (((x1+x2)/2), ((y1+y2)/2)))
Distance Formula
d = √(x2 − x1)^2 + (y2 − y1)^2
New X-Coordinate
x1+(r1/(r1+r2))(x2-x1)
New Y-Coordinate
y1+(r1/(r1+r2))(y2-y1)
Triangle Inequality Theorems
- sum of two sides
- difference of two sides
- longest side opposite of
- shortest side opposite of
- The sum of 2 sides must be greater than the third side
- The difference of 2 sides must be less than the third side
- The longest side of the triangle is opposite the largest angle
- The shortest side of the triangle is opposite the smallest angle
Isosceles Triangle
- relationship between sides and angles
- altitude is also?
- 2 ≅ sides and 2 ≅ base angles
- The altitude drawn from the vertex is also the median and
angle bisector - If two sides of a triangle are ≅, then the angles opposite
those ≅ sides are ≅.
Side-Splitter Theorem
If a line is parallel to a side of a triangle and intersects the other two sides, then this line divides those two sides proportionally.
Triangle Congruence Theorems
SSS
SAS
ASA
AAS
HL
CPCTC
Corresponding Parts of Congruent Triangles are Congruent
Similar Triangle Theorems
AA
SAS
SSS
Similar figures have
Similar figures have congruent angles and proportional sides
Similar-Proportional Sentence
Corresponding Sides of Similar Triangles are Proportional
means/extremes
In a proportion, the product of the means equals the product of the extremes
Geometric Mean
multiply numbers together, take the square root
Altitude Theorem
The altitude is the geometric mean between the 2 segments of the hypotenuse.
Leg Theorem
The leg is the geometric mean between the segment it touches and the whole hypotenuse.
Reflection
r
Rotation
R