1 / 10

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

There’s a quiz on the table. Please take one and get started. 3.8 Analyzing Polygons with Coordinates. First, some definitions. Positive slope. Negative slope. Slope (a review from Algebra I). Slope is the steepness of a line.

daveigh
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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. Positive slope Negative slope Slope (a review from Algebra I) • Slope is the steepness of a line. • Slope can be found using 2 points, (x1, y1) and (x2, y2), in the formula: y2 – y1 x2 – x1 • 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.

  4. Try this • 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

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

  6. Try this • 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

  7. Midpoint Formula The midpoint of a segment whose endpoints are (x1, y1) and (x2, y2), has the coordinates x1 + x2y1 + y2 • , 2 ( ) Try this Find the coordinate of the midpoint of the segment whose endpoints are (-4, 9) and (8, -10) (2, -1/2)

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

  9. More Practice (not hard, but it does take time) 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.

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

More Related