Let’s grade homework Pg 138 – 143; 5-9, 17-21, not 8c

Proportional Equations – Using Proportional equations

Ratio A comparison of 2 things. Can be written like: Dogs : cats (in words) 2:1 (with a colon) 3 (as a fraction) 4 An equation where 2 ratios are equal to each other Written like: (3 + x) = Use cross products to solve. Proportion

How are ratios and proportions the same? How are they different?

I will number each row. Back person: please get the appropriate paper from the back table – one paper for each person – and hand them out. Second person from the back: please get a straightedge for everyone in your row. Everyone: please follow the instructions on the paper and complete your paper independently. In 5 minutes, you will be able to compare your answers to others in your row to come up with a final solution. Then, make a table and come up with some conjectures..

Put a point of dilation somewhere inside the shape. Measure the sides of your shape in cm. Dilate the shape by a scale factor of 2. Find the perimeter of the pre-image. Find the perimeter of the image. Find the area of the pre-image. Find the area of the image. #4 #2 #3 #1 #5

shape 1shape 2shape 3shape 4shape 5 perimeter of pre-image perimeter of image area of pre-image area of image

Naming & Comparing Polygons ♥List vertices in order, either clockwise or counterclockwise. ♥When comparing 2 polygons, begin at corresponding vertices; name the vertices in order and; go in the same direction. ♥By doing this you can identify corresponding parts. A D C B E DCBAE P I J K H IJKPH  D corresponds to  I AE corresponds to PH

Name corresponding parts Name all the angles that correspond: A D C B E P I J K H  D corresponds to  I  C corresponds to  J  B corresponds to  K  A corresponds to  P  E corresponds to  H DCBAEIJKPH Name all the segments that correspond: DC corresponds to IJ CB corresponds to JK BA corresponds to KP AE corresponds to PH ED corresponds to HI How many corresponding angles are there? How many corresponding sides are there? 55

How many ways can you name pentagon DCBAE? A D C B E 10 Do it. DCBAE CBAED BAEDC AEDCB EDCBA Pick a vertex and go clockwisePick a vertex and go counterclockwise DEABC CDEAB BCDEA ABCDE EABCD

Similarity Statements Given: These polygons are similar. Remember, if they are SIMILAR, corresponding sides have the same RATIO. G H F E C D B A ABCD ~ EFGH AB ~ EF DA ~ HE DC ~ HG CB ~ GF SIMILARITY STATEMENTS SIMILARITY STATEMENT

Corresponding angles in a similar figure are congruent!!

Corresponding angles in a similar figure are congruent  A  E  B  F  D  H  C  G C D B A G H F E = ~ = ~ = ~ = ~

Quick check How many different ways can you name ΔABC? What is the relationship of corresponding sides in a similar figure? What is the relationship of corresponding angles in a similar figure? What happens to the perimeter of a shape that has been dilated by a scale factor of 2? What happens to the area of a shape that has been dilated by a scale factor of 2? What is the simplified, exact answer to: √3 + 5√3 ? What is the name of angle pair c and h?c and h Are angles c and h congruent, supplementary or neither? Defend your answer.c and h What is the name of angle pair b and g?b and g What is the measurement relationship between b and g? Defend your answer.b and g What is the sum of the angles in a triangle? What is the sum of the angles in a quadrilateral? If a shape has a scale factor of 3, is the pre-image larger or smaller than the image?

a d b hg e c f

Your assignment Pg 146 – 151; 27-31, 38-42