2. If a is positive, b is negative, and c=0, which of the following expression is positive? a. a(b+c)b. c(a+b) c. b(b-a+c) d. c(a-b+ab) 2.6 warm-up 10

3. If a is positive, b is negative, and c=0, which of the following expression is positive? a. a(b+c)b. c(a+b) c. b(b-a+c) d. c(a-b+ab) 2.6 warm-up 10

4. You will use deductive reasoning to prove a statement. You will also select an appropriate representation in order to solve problems.

5. Pardekooperu Lets start off with some theorems. If two lines are parallel to the same line, then they are parallel to each other. a b c a || b b || c, If and then a || c.

6. Lets start off with some theorems. In a plane, if two lines are perpendicular to the same line, then they are parallel to each other. a b c a  b b  c, If and then a || c

7. One last theorems. In a plane, if a line is perpendicular to one of two parallel lines, then it is also perpendicular to the other. a b c a  b,b  c. If and then a || c

8. Lets try a problem. Draw a picture and then form a conclusion about line a and c. a  b a b b || c c a  c Look at a and c. What conclusion can be drawn ? Now write a conditional statement. If a  b, and b || c, then a  c.

9. Just one more. Draw a picture and then form a conclusion about line a and d. a || b a b b || c c c || d d Look at a and d. What conclusion can be drawn ? a || d Now write a conditional statement. If a || b, b || c, and c || d, then a || d.

10. Assignment Worksheet 3.3

11. 3.3 Parallel and Perpendicular Lines Pardekooper Geometry Draw a picture for the following, form a conclusion about line a and d, and then write a conditional statement. 1.a || b, b || c, c  d2. a || b, b  c, c || d3. a  b, b || c. c || d 4.a || b, b  c, c  d5. a  b, b || c, c  d6. a  b, b , c || d drawing: conclusion:___________ conditional statement: ________________________ ________________________ _____________________ conclusion:___________ conditional statement: ________________________ ________________________ _____________________ conclusion:___________ conditional statement: ________________________ ________________________ _____________________ conclusion:___________ conditional statement: ________________________ ________________________ _____________________ conclusion:___________ conditional statement: ________________________ ________________________ _____________________ conclusion:___________ conditional statement: ________________________ ________________________ _____________________