Bell work: Solve each proportion 9 = a = 3 m + 1 m

Lesson 7-1: Ratios of Similar Polygons Rigor: Determine if 2 figures are similar, determine the similarity ratio, and calculate side lengths of similar polygons Relevance – Indirect measurement and scale models

What are Similar Figures?  Similar figures – have the same shape, but not necessarily the same size  Symbol is ~  Turn to page 281 in the core book for formal definition and examples 1 & 2

EX 3: Determining Similarity Are the polygons similar? If so, write a similarity statement and determine the scale factor. a)b)

Notes: Scale Drawings  Scale Drawings/models – all drawing/model lengths are proportional to corresponding actual lengths  Ratios (Scales) of scale drawings can have different units!  Example = 1cm : 200m

Ex 4: Scale Drawings A boxcar has the dimensions shown. A model of the boxcar is 1.25in wide. Find the length of the model to the nearest inch.

Ex 5: Scale Drawings The Seattle Space Needle is 605ft tall. Tommy decides to make a scale drawing on an 8.5in by 11in piece of paper. If Tommy chooses a 1in : 50ft scale, is his paper big enough?

7-1 Classwork from the core book  Pg 285 and 286 ALL 7-1 Homework from Core book  Pg 283 #1 – 3 and pg 284 ALL  Due Tuesday for periods 1, 3, 5, 7  Due Wednesday for periods 2 & 4