1. Opener: On your new opener sheet, use the square below to help you explain
why the area formula (discussed last class) for regular polygons
works. You have until 7:45. (Remember that you must be working at
the bell in order to get credit).
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2. 9.2: Circles and Regular Polygons
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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?
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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.
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5. Homework Questions: Take the next 5‐10 minutes to work with your partner
on any homework questions that you had prior to class today.
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6. 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?
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7. 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.
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8. 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?
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9. Raffle #6: Find the shaded area of the regular hexagon donut below.
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10. 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 hundredth.
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