Similar Figures will all have the same ratio

Similar Figures will all have the same ratio between corresponding sides

Whatever the scale factor is between two similar polygons, it will be identical to the scale factor of the perimeters

If you SQUARE the scale factor between two similar figures, it will give you the scale factor between AREAS

Answers to 8. 1 HW: This will be checked next week.

Remember the Triangle CONGRUENCE theorems: SAS, ASA, SSS, AAS, and HL. There also ways to prove Triangles are SIMILAR to each other. Remember that Similar means the same shape, but not necessarily the same size.

Can you prove triangles congruent if you have two pairs of angles congruent? Do these triangles HAVE to be similar if they have two pairs of angles congruent?

First thing: If two angles are congruent in two different triangles, then the third angles MUST be congruent

These triangles have to be similar, so if you have two pairs of congruent angles in two different triangles, the triangles will be similar. This is known as the Angle-Angle theorem (Angle-Angle also works)

Proving Triangles Similar- done as a short-answer proof. Do example 1 in your groups. How would you prove these similar?

Do example 2 in your groups. How would you prove these triangles similar?

Could also use corresponding angles converse to show lines parallel on example 2 a, and then use corresponding angles theorem to get the 2 nd pair of angles congruent. Could also use vertical angles in example 2 b

Shadow problems: In these examples, set up a proportion and solve for the missing side

Homework: 8. 2 1 -26 ALL. Also do the Shadow Problems worksheet. On Friday, do the mid chapter quiz