Week 28 CAPT Problem - 9th Grade


Circles


The table below shows that the value C, the circumference of a circle, is dependent on d, its diameter.

d units C units
1 3.14
2 6.28
3 9.42
4 12.56
.
.
.
 		.
.
.
10 31.4

An equation that shows the relationship between the diameter of the circle and its circumference is C = Πd where 3.14 is used for Π.

  1. What is the circumference of the circle when the diameter is 6?

  2. What is the diameter of the circle with a circumference of 26.69 units?

  3. Draw a line graph that shows the relationship between the diameter of a circle and its circumference. Be sure to label the both axis.

  4. Explain how you could use your graph to approximate the circumference of a circle with a diameter of 9 units.