2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
Math Humor
Q: What do you have to know to get
top grades in geometry?
A: Al
1
2­6 geometric proof 1AB.notebook
OBJECTIVE:
theorem
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
any statement that you can prove
once proven can be used as reason in later proofs.
a deductive argument for a mathematical
statement
↳
begins with Given and Prove statements
→
two­column
proof
restates hypothesis & conclusion of conjecture
conjecture
stmt believed to be true but not yet proven
2
2­6 geometric proof 1AB.notebook
OBJECTIVE:
writing
a *
proof
*
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
justify each logical step with a reason
can use symbols and abbreviations
clear ­ anyone who reads proof will understand
3
2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
process
4
2­6 geometric proof 1AB.notebook
OBJECTIVE:
Ex 1
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
Write a justification for each
step, given that ∠A and ∠B are
supplementary and m∠A = 45°.
1. ∠A and ∠B are supplementary.
m∠A = 45° Given information
2. m∠A + m∠B = 180° Def. of supp ∠s 3. 45° + m∠B = 180°
Subst. Prop of = Steps 1, 2
4. m∠B = 135° Subtr. Prop of = 5
2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
When a justification is based on more than the previous step
you can note this after the reason
this may help your logical reasoning
6
2­6 geometric proof 1AB.notebook
OBJECTIVE:
Ex 2
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
Write a justification for each step, given that B is the midpoint of AC and AB ≅ EF.
1. B is the midpoint of
.
2.
3.
4.
5.
7
2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
8
2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
9
2­6 geometric proof 1AB.notebook
OBJECTIVE:
February 18, 2015
Write two­column proofs. Prove geometric
theorems by using deductive reasoning.
geometric
proof
Given
Prove
10