1. There’s a quiz on the table. Please take one and get started.

2. 3.8 Analyzing Polygons with Coordinates First, some definitions

3. Slope (a review from Algebra I) ♥Slope is the steepness of a line. ♥Slope can be found using 2 points, (x 1, y 1 ) and (x 2, y 2 ), in the formula: y 2 – y 1 x 2 – x 1 ♥Slope is abbreviated by the letter ‘m’. ♥Slope is always referred to as ‘rise over run’. ♥In the equation y = mx + b, m is the slope of the line. ♥A line with positive slope rises from left to right. ♥A line with negative slope falls from left to right. Positive slope Negative slope

4. ♥Find the slope of the line that contains the points (3, 4) and (-1, 0). 4 – 0 = 4 = 1 3 - -1 4 ♥Find the slope of the line that contains the points (5, 24) and (1, 9) 24 – 9 = 15 5 – 1 4 Try this

5. Parallel and Perpendicular lines y = 3x + 5 y = -1/3x – 2 are perpendicular lines. DOUBLE WHAMMY!! NEGATIVE AND RECIPROCAL Lines are perpendicular if they have the NEGATIVE RECIPROCAL slope of each other. If lines have the SAME SLOPE, they are parallel. (All vertical lines are parallel). y = 3x + 10 y = 3x -45 are || lines

6. ♥If one line has the points (1, 3) and (4,8) and another line has the points (3,5) and (6, 10), tell if the lines are parallel, perpendicular or neither. You have to check the slope in both lines. 3 – 8 = -5 = 5 1 – 4 -3 3 5 – 10 = -5 = 5 3 – 6 -3 3 Since the slope is 5/3 in both lines, the lines are parallel Try this

7. Midpoint Formula The midpoint of a segment whose endpoints are (x 1, y 1 ) and (x 2, y 2 ), has the coordinates x 1 + x 2 y 1 + y 2 2, 2 () Find the coordinate of the midpoint of the segment whose endpoints are (-4, 9) and (8, -10) (2, -1/2) Try this

8. Find the coordinate of the midpoint of the segment whose endpoints are (7, 12) and (0, -1) (3.5, 5.5) Try this

9. If a triangle has vertices at A (0, 1), B (5,4) and C (6, 0), how can you tell if it is a right triangle? You have to check the slope of each segment. If one is the negative reciprocal of the other, then there is a right angle in the triangle. Find the slope of AB 3/5 Find the slope of BC 4/-1 = -4 Find the slope of AC 1/-6 Is one slope the negative reciprocal of another? If so, we have a right triangle. Nope. No right triangle. More Practice (not hard, but it does take time)

10. Assignment Pg 194, 12-28 evens and 52-57 evens and odds