day 61 · day 61 1. opener a & b) give the translation. c) a certain regular polygon has...

Day 61

1. Openera & b) Give the translation. c) A certain regular polygon has

apothem = 15 inches. Its perimeter = 80 inches. What is its area?

d) Each of its sides is 10 inches long. What kind of regular polygon is it?

e) What is the only food that doesn’t spoil?

2. Famous Idiots in HistoryIn February, 2005, police officers discovered 3 million nickels buried in the backyard of a Florida home. They were part of a 45,000 pound shipment of nickels that was stolen the previous December.

2. Famous Idiots in History

Clad Lincoln Jefferson FDR GW JFK AnthonySacagaw

ea

$ .01 .05 .10 .25 .50 1.00 1.00

grams 2.5 5 2.268 5.670 11.340 8.1 8.1

$/g .004 .01 .044 .044 .044 .123 .123

3. Area of a CircleWhat is the area?

€

A = πr2

3. Area of a CircleWhat is the area?

3. Area of a CircleWhat is the area?

3. Area of a CircleWhat is the area?

r

half the circumference

3. Area of a CircleWhat is the area?

r

πr

3. Area of a CircleWhat is the area?

€

A = πr2

3. Area of a CircleWhat is the area?

€

A = πr2

9 in.

€

A = π 9( )2

€

A = 81π sq. inches

3. Area of a CircleWhat is the radius?

A = 33 sq. inches

4. Classworkpg. 435 // #1 - 8, 12 - 15

Or: give a formula for area (A) in terms of circumference (C)

5. Break

6. Show and Tell

7. Sectors, Segments, and AnnulusesWhat is the area?

Annuli

Sector Segment Annulus

r

a°a°

rr R

a fraction of the circle the sector minus a triangle a big circle minus a small one

€

A =a360

πr2

€

A =a360

πr2 − 12bh

€

A = πR2 −πr2

8. Classworkpg. 439 // #1 - 14

9. HomeworkBring compass.

Find the area of a stop sign in square inches.