GEOMETRY Failing to plan is planning to fail. Today: 11.3 Check 11.4/11.5 Instruction Practice

GEOMETRYFailing to plan is planning to fail.

Today: 11.3 Check 11.4/11.5 Instruction Practice

Objectives:1. Find the circumference and area of circles

2. Find the length of arcs

3. Find the areas of sectors

4. Use circumference and arc lengths in real life

5. Find areas of circles & sectors in real life

Vocabulary: arc length, sector

11.4/11.5 Applications of Circumference and Area of Circles

You and 2 friends order a 18” pizza. If the pizza is cut into 8 pieces and you eat 3, how much of the pizza did you eat?

Find the amount of pizza you ate to the nearest tenth.

Portion or “slice” of a circle is called a sector.

Find the area of sector XYZ to

the nearest tenth.

X

ZY

A ≈ 142.5 m2

135°11m

If the area of sector is 34 m2 and the radius is 6m, find the central angle to the nearest degree.

mD ≈ 108°

E

F

O

D

Remember our satellites from Chapter 10?

If the radius of the earth is 4000 and BDC = 50°

find how many miles the satellite covers.

Find the arc length of XZ to the nearest tenth.

X

ZY

x ≈ 25.9 m

135°11m

Find the mXZ to the nearest degree.

X

ZY

16.76 m

8 m

mLM ≈ 120°

Failing to plan is planning to fail.

Assignment: 11.4/11.5 p 705 #1-7

and p 712 #6-10 Test Chapter 11 on

Friday Bridge Monday due

Friday

GEOMETRY

GEOMETRYFailing to plan is planning to fail.

Today: HW Check 11.5/11.6 Cont. Practice

Failing to plan is planning to fail.

Assignment: 11.4/11.5 p 705 #1-7

and p 712 #6-10 Test Chapter 11 on

Friday Bridge Money due

Friday

GEOMETRY

Homework Quiz

Take out a piece of notebook paper label it CHAPTER 11 HOMEWORK QUIZ.

Write down the date (3/17), then write out p 705 #5, include your picture, work and answer.

Objectives:1. Find the circumference and area of circles

2. Find the length of arcs

3. Find the areas of sectors

4. Use circumference and arc lengths in real life

5. Find areas of circles & sectors in real life

Vocabulary: arc length, sector

11.4/11.5 Applications of Circumference and Area of Circles

Find the circumference of Y to the nearest tenth.

X

ZY

10.2 cm

C ≈ 81.6 cm

45°

What is the radius of a circle to a tenth when a 50° sector has an area of 120 ft2.

r ≈ 16.6 ft

J K

OL

If mDCG = 120° and DC = 24, find the probability that a randomly choosen point is in sector DCG.

33%

D

G

O

C

Failing to plan is planning to fail.

Assignment: Review 11.3-11.6

p711 #9-18 Test Chapter 11 on

Friday Bridge Money due

Friday

GEOMETRY

Homework Check

Review 11.3 – 11.6 p 711 #9-18

9.) perim 4:3, area 16:9 10.) 31.5 cm2

11.) 78.54 cm2 12.) 9.16 cm13.) 22.91 cm2 14.) 353.43 ft2

15.) 547.34 in2 16.) 51.3 m2

17.) 78.5% 18.) 12.5%