9 2 Notes (D1) B
- 1. Opener: Please write your solution to one of the homework problems up on the board. Sign your name to your problem. Do the 3 problems below on your opener sheet. When you are done, please place the opener sheet on my desk. 1. What is the formula for the area of a circle? 2. What is the formula for the circumference of a circle? 3. Find the area and circumference of a circle with diameter of 8cm. 1
- 2. 9.2: Circles and Regular Polygons 8 10 6 2
- 3. 1. Find the area of a regular heptagon with a side of 4 cm. 2. Find the area of a regular pentagon with an apothem of 3cm. Would you have to use trig if you were dealing with a hexagon? A nonagon? An equilateral triangle? 3
- 4. 3. Find the area of a circle with radius of 3x inches. 4. If a circle has an area of 12 cm2. Find the circumference. 4
- 5. Math Raffle: All your work, as well as the original problem, should be written in your notes for today. Only write your answer on the math raffle ticket. Raffle #1: If the area of a regular polygon is 302.4 cm2 and the apothem is 9.6 cm, what is the perimeter of the polygon? 5
- 6. Raffle #2: Find the side length of a regular heptagon with a radius of 6 inches and an area of 48 in2. Raffle #3: Find the area of a regular octagon with a radius of 12 cm. 6
- 7. Raffle #4: If the circumference of a circle is 13π inches, what is the area of the circle? Raffle #5: If an equilateral triangle is inscribed inside a circle of radius 20 ft, what is the area of the region inside the circle but outside the triangle? 7
- 9. Exit Slip: Please complete #12 and 16 on page 603 with your partner. Turn in one sheet of paper with both names at the top of it. Next to one name, put the letter A and next to the other name, put the letter B. Person A should be writing for the first problem, and person B should be writing for the second problem. Show all your work and include labeled diagrams (just like we did in our notes today). For #12, keep your answer in terms of π (exact!). For #16, round to the nearest tenth. 9