Download Geometry Informal and Two-Column Proofs Two

Geometry
Informal and Two-Column Proofs
Two Column Proofs Assignment
Total Points = 40
This proof is worth 10 points. Each blank is worth 2 points.
Fill in the blanks in the proof below:
A
B
C
D
E
G
F
H
Given: CD⊥ AE and CD||GH ; Prove: GH⊥ AF .
Statement
Reason
CD⊥ AE
Given
CD||GH
Given
∠ABD is a right angle
Because CD is perpendicular with AE
∠ABD and ∠GEF are alternate exterior
angles
∠ABD ≅ ∠GEF
Because CD // GH
∠GEF is a right angle
All right angles are congruent
GH is perpendicular with AF
Definition of alternate exterior angles
Proved
This proof is worth 30 points, 15 points for statements, 15 points for reasons
A
B
F
G
C
E
D
Given: m∠EGF = 60° and m∠AGF = 90° ; Prove: m∠AGB = 30° .
Angle on 1 side of a straight line will always add to 180 degrees.
Therefore, mEGF + mAGF + mAGB = 180
--> mAGB = 180 - 60 - 90 = 30 degrees