Proofs with Angles

<1 and <2 are a linear pair

<1 and <3 are right angles

<2 and <4 are vertical angles

 $<1\cong<3$  

m<1 + m<2 = 180

m<1 + m<2 = 90

m<1 = m<2

nothing

If x = 5 and and x = y, then y = 5.

If x = y then y = x

x = x

If 2x + 4 = 2, then x = -1

PF = QF

F is the midpoint of PQ

m<PFA = m<QFA

<PFQ is a straight angle

GH and AB intersect at D

<GDA and <HDB are vertical angles

D is the midpoint of GH

G, D, and H are collinear

lines l and m are perpendicular

<a and <b are adjacent

<a and <b are complementary

m<a = m<b