Area/Circumference of a Circle

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Slide 1: Interactive video with 7 slides
math

This lesson contains 8 slides, with interactive quizzes, text slides and 1 video.

Items in this lesson

Slide 1 -Video

00:13
Value of Pi
For the purposes of this lesson, we can use either 3.14 or 22/7 for the value of Pi.
If you have a scientific calculator, the π sign will also get you Pi!

Slide 2 -Slide

01:00
Formula for Diameter
d = r x 2

Slide 3 -Slide

01:00
Try it!
If the diameter of the circle was 8 cm, what is the circumference?
A
11.14 cm
B
4.86 cm
C
25.12
D
2.54777 cm

Slide 4 -Quiz

01:20
Quick review on exponents!
"r squared" or "r raised to the second power" is the same as...
A
r x r
B
r x 2
C
r + r
D
r x r x r

Slide 5 -Quiz

02:29
Try it!
If the radius of the circle was 4 cm, what is the area?
A
11.14 cm squared
B
12.56 cm squared
C
35.16 cm squared
D
50.24 cm squared

Slide 6 -Quiz

05:46
What's the circumference of the Earth? Choose the closest answer.
A
4,060.51 km
B
40,035 km
C
12,753.14 km
D
80,070 km

Slide 7 -Quiz

06:35
What's the pizza's area?
Remember, to get the radius, you must divide the diameter in half!
A
452.16 square inches
B
45.859 square inches
C
37.68 square inches
D
147.14 square inches