Geometry: Midterm formulas etc.

Question 1

area triangle

Answer 1

1/2bh

Question 2

area rectangle

Answer 2

bh

Question 3

area trapezoid

Answer 3

(b1+b2)h/2

Question 4

area circle

Answer 4

pi(r)squared

Question 5

area regular polygon

Answer 5

1/2(apothem x side)x(# of triangles)

Question 6

complementary angles

Answer 6

two angles sum is 90

Question 7

supplementary angles

Answer 7

two angles sum is 180

Question 8

sum of interior angles

Answer 8

180(n-2)

Question 9

sum of exterior angles

Answer 9

360

Question 10

each interior angle of a regular polygon

Answer 10

180(n-2)/n

Question 11

each exterior angle of a regular polygon

Answer 11

360/n

Question 12

distance formula

Answer 12

d=square root of(x1-x2)squared + (y1 - y2)squared

Question 13

midpoint formula

Answer 13

(x1+x2)/2 , (y1+y2/2)

Question 14

slope formula

Answer 14

m=(y1-y2)/(x1-x2)

Question 15

slope intercept form of a line

Answer 15

y=mx+b

Question 16

point slope formula of a line

Answer 16

y-y1=m(x-x1)

Question 17

distance from a point to a line

Answer 17

IAx+By+cI / square root of Asquared+Bsquared

Question 18

pythagorean theorem

Answer 18

a(squared)+b(squared)=c(squared)

Question 19

trig.

Answer 19

SOHCAHTOA

Question 20

what does the measure of one exterior angle =

Answer 20

sum of 2 non-adjacent interior angles

Question 21

what are ways to prove that triangles are congruent

Answer 21

ASA
SSS
SAS
AAS
HL

Question 22

medium

Answer 22

goes from one vertex to the midpoint of the opposite side

Question 23

altitude

Answer 23

goes from one vertex, perpendicular to the opposite side

Question 24

perpendicular bisector

Answer 24

perpendicular to a side through the midpoint

Question 25

angle bisector

Answer 25

cuts an angle in half

Question 26

centroid

Answer 26

the intersection of the medians of a triangle

2/3 distance from each vertex to midpoint

Question 27

incenter

Answer 27

the intersection of the angle bisectors of a triangle

Question 28

circumcenter

Answer 28

the intersection of perpendicular bisectors of a triangle

Question 29

orthocenter

Answer 29

the intersection of the altitudes of a triangle

Question 30

converse

Answer 30

switch order

Question 31

inverse

Answer 31

negate

Question 32

contrapositive

Answer 32

flip and negate

Question 33

law of detachment

Answer 33

p->q
p
q

Question 34

law of contrapositives

Answer 34

p->q

~q->~p

Question 35

law of disjunctive inference

Answer 35

pvq
~p
q

Question 36

DeMorgan’s Law

Answer 36

~(PvQ)

~pA~q

Question 37

Law of Modus Tollens

Answer 37

p->q
~q
~p

Question 38

Chain Rule

Answer 38

p->q
q->r
p->r

Question 39

axis of symmetry

Answer 39

-b/2a

Question 40

what does a midpoint and a bisector do

Answer 40

splits a segment into 2 congruent parts

Question 41

5 step process

Answer 41

state pair of congruent angles/segments
state second pair of congruent angles/segments
show segment addition/subtraction postulate
show that congruent’s added/subtracted from congruent’s are congruent
stated desired congruent segments by substitution

Question 42

vertical angles

Answer 42

are congruent

Question 43

right angles

Answer 43

are congruent

Question 44

reasons to proof with angles:

complements

Answer 44

form right angles
complements of same angle are =
complements of =s <s are =

Question 45

reasons to proof with angles:

supplements

Answer 45

form straight lines
supps of same < are =
supps of = <s are =

Question 46

reasons to proof with parallel lines

Answer 46

alt. interior <s
2 lines II to same line then they are II
2 lines perpendicular to same line then they II

Question 47

reasons to proof with perpendicular lines

Answer 47

form right angles

transversal is perpendicular to one of 2 II lines, then it is perpendicular to the other