1 / 9

1.11 Day 3

1.11 Day 3. Please grab your calculators on your way into the room and start on the Bell Ringer. Bell Ringer. Find a pair or group of angles that have an invariant sum of 180 degrees. If you move point D along line C, will the area of triangle DEF change.

darrel-vaughan
Download Presentation

1.11 Day 3

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. 1.11 Day 3 Please grab your calculators on your way into the room and start on the Bell Ringer. Bell Ringer Find a pair or group of angles that have an invariant sum of 180 degrees. If you move point D along line C, will the area of triangle DEF change.

  2. What is the sum of the measures of the angles of a 20-sided polygon? 9-sided polygon? 17-sided polygon? 20 Sided – 3240 degrees 9 sided – 1260 degrees 17 sided – 2700 degrees What is the measure of each angle in a 9 sided polygon? 1260/9 = 140 degrees

  3. What is the area of the shaded region? Area of square – area of circle = shaded region L X W 8 x 8 – ( (3.14) x 42 ) 64 – 50.24 = 13.76

  4. What relationship do you see between the lengths of CD and DA, as well as AE and EB? CD = DA (because D is the midpoint of segment AC) AE = EB (because E is the midpoint of segment AB)

  5. Compare the lengths of segment DE and segment CB as you drag one of the vertices. As segment CB gets larger, so does segment DE. DE/CB = ½ 2DE = CB or 1/2CB = DE

  6. A segment connecting the midpoints of two sides of a triangle is parallel to the third side and is half its length. Midline Conjecture AD/AC AE/AB DE/CB Area of triangle AED/Area of triangle ABC What invariants did you find in triangle ABC as you moved one of the vertices?

  7. What is the length of segment AD, EC and BC?

  8. What is the length of segment AD, DB, EC, and DE

  9. Homework • Given that DE is a midline: • If DE = 10, find the length of CB. • If CB = 10, find the length of DE. • If AC = 14, find EC. • If AD = x + 5 and DB = 20, find the value of x and find the lengths of AD and AB. • If DE = 6 and CB = 3x – 4, find the value of x. • f) If the height of the triangle is 7cm and the base of the triangle is 6 cm. What is the area of the triangle?

More Related