Chapter 7 Section 1

 Students will write ratios and solve proportions.

 A comparison of two quantities by division  They can be written in three different ways A:B A to B A/B

 Look at Problem 1  Try the “Got It” problem for this example.

 Compares three or more numbers  In the ratio A:B:C The ratio of the first two is A:B The ratio of the second two is B:C And the ratio to the first and last is A:C

 Look at Problem 3  Try the “Got It” problem for this example.

 An equation of two (equal) ratios.  Proportions are solve by cross multiplication

 The first and last numbers in the proportion.

 The second and third numbers in a proportion

 A:B = C:D  A and D are the extremes  B and C are the means

 Finding the product of the means and the product of the extremes is called cross multiplication or cross products.  It is used to solve a proportion.

 Look at Problem 4  Try the “Got It” problem for this example.

1. If A:B = C:D then B:A = D:C 2. If A:B = C:D then A:C = B:D 3. If A:B = C:D then A + B = C + D BD

 Look at Problem 5  Try the “Got It” problem for this example.

 Try problems #1-8 on your own

 Complete problems #9-36.

 Compare/Contrast similar triangles and congruent triangles (at least 6 sentences).  When finished complete #61-65 on page 438.