Geometry

Today:• 8.1 Check• 8.2 Instruction• 8.2 Practice

I submit to you that if a man hasn’t discovered something he will die for he isn’t fit to live.

Martin Luther King

Yesterday

Assignment:• 8.1 p 462 #29,

31, 46-50, 63-66

• Quiz 8.1-8.3 Tuesday

I submit to you that if a man hasn’t discovered something he will die for he isn’t fit to live.

Martin Luther King

Homework Quiz

Take out a piece of notebook paper label it CHAPTER 8 HOMEWORK QUIZ.

Write down the date (1/9), then write out p 462 #47 (INCLUDING PICTURE!!!), your work and your answer.

8.2 Problem Solving in Geometry with ProportionsObjectives:1. Find the geometric mean of two

numbers2. Use properties of proportions3. Use properties of proportions in real

life

Vocabulary:geometric mean

X is the geometric mean of a and b

The mean (x) always appears twice.

Find the geometric mean of 8 and 18.

x = 12

bx

xa

Geometric Mean:

extremes

means

8 x

x 16

8.2

a b

Find the geometric mean of 5 and 75.

WRITE X TWICE!x2 =

375

8.2

No-No’s of RadicalsNo-No’s of Radicals

1.1. No decimalsNo decimals

2.2. No perfect squares in No perfect squares in radicalsradicals

3.3. No fractions in radicalsNo fractions in radicals

4.4. No radicals in the No radicals in the denominatordenominator

54 180

Find the geometric mean of 5 and 75.

WRITE X TWICE!x2 =

375

Find the geometric mean of and .

X = 4

Find the geometric mean of 30 and 5.

155x

8.2

x 5 6

8 32

A scale model of a car is 10 inches long and 5 inches tall. The actual car is 3 feet tall. What is the length of the actual car?

Real Life

8.1

6’6’

Long vs TallModel ____ ____Actual

A map has a scale ratio of 2” : 25 miles. If the distance between to cities is 3.5” on the map, how far is it in real life?

43.75 miles43.75 miles

Real Life

8.1

Students wanted to make a statue honoring Mr. Pelzer. The model of the statue is shown below. The model’s height is 18” and the base is 5”. If the real base is 12’, how tall is the statue?

h = 43.2’If the statue’s calculator is 3’, how large is the model’s one?

h = 1.25”

8.2

You are building a scale model of your uncles’ fishing boat. The boat is 62 ft long and 23 ft wide. The model will be 14 in long. How wide should it be?

h = 5.2 inThe mast of your uncles fishing boat is 30 ft tall. How tall should the mast be on the model?

h = 6.8 in8.2

Assignment:• 8.2 p468 #18,

20, 22, 31-32, 44-45

• Quiz 8.1-8.3 Tuesday

Geometry

I submit to you that if a man hasn’t discovered something he will die for he isn’t fit to live.

Martin Luther King