1. Objectives: Students will use a ruler to measure diameters of circles and then find area and circumference of circles. M11.C.1

2.  On your paper, label each Vocabulary word: -circle -center -diameter -radius -semi-circle -major arc -minor arc

3.  The circumference of a circle is the distance around the circle. The number pi (π) is the ratio of the circumference of a circle to its diameter.  In your own words, what is another word for circumference? Think about the distance around other shapes such as a triangle or quadrilateral.

4.  The circumference of a circle is π times the diameter.  C = πd or C =2πr  Why are both formulas above correct when finding the circumference? *Circumference is noted using single units. Ex: inches, feet, etc.

5.  The area of a circle is the number of square units the figure encloses.  The area of a circle is π times the radius squared.  A = πr² **Area in noted using squared units. Ex: inches squared, feet squared, etc

6.  Circle G has a radius of 14 cm. Find the circumference of circle G in terms of π. Then find the circumference to the nearest tenth.

7.  Find the area of circle B in terms of π. Then find the area to the nearest tenth. B 8.4 in

8.  Using a ruler, measure the diameter of your 5 circular items and record them in the chart provided.  Continue to fill in the chart by finding the radius, area, and circumference of each circle.  Once your chart is complete, give it to your partner along with the circular items so that he/she can check your measurements and calculations.  With your partner, answer the analysis questions.

10.  Circles that lie in the same plane and have the same center are concentric circles.

11.  A circular swimming pool with a 16 foot diameter will be enclosed in a circular fence 4 feet from the pool. What length of fencing material is needed? Round to the nearest whole number.

12.  Brainstorming with your partner, make a list of at least five jobs/careers that would require you to find the area or circumference of a circle. What companies would hire these types of workers?  Write two paragraphs incorporating the careers and jobs that would require finding area and circumference. Would you be interested in one of those jobs in the future?  You will share your ideas with the class.