Friday, January 6, 2012

Friday, January 6, 2012• No HW. • Study for Ch. 7 on Wed 1/11• Warm Up –

Complete #20 on back of HW – “An architect …”

An architect …

Agenda• Review of Area of Irregular Figures• Review Study Guide• Practice with finding area

Area of Irregular Figures• Don’t assume anything!

Study Guide1. About 16 in2

2. About 10 in2

3. A = (9)(12) = 108 cm2

4. A = ½ (16)(24) = 192 in2

5. A = ½ (7.5)(5+10) = 56.25 m2

6. A = triangle + square= ½ (8)(12) + (12)2

= 48 + 144 = 192 cm2

Study Guide7. C = 2πr = 2(3.14)(4) =

25.12 cmA = πr2 = (3.14)(4)2 = 50.24 cm2

8. d = 2r = 25 mmr = 12.5 mmC = 2πr = 2(3.14)(12.5) = 78.5 mmA = πr2 = (3.14)(12.5)2 = 490.625 mm2

Cold Call!

How do you find the area?Keep your study guide out!

What is pi (π)?

Additional Practice• What did the scientist say to the

hydrogen atom that claimed to have lost an electron?

• What happened when the TV set asked the remote control for a date?

• Answers will be posted at www.teachervivian.com