Chapter 11.5/11.6: Circumference and Area of Circles

Question 1

Circumference

Answer 1

the distance around the circle.

Question 2

Thm. 11.8 - Circumference of a Circle

Answer 2

for all circles, the ratio of the circumference, C, to the diameter, d, is the same. This ratio c/d is denoted by the number 3.14. Thus, the circumference of a circle is C=3.14d, or C=2 x 3.14r.

Question 3

Arc length

Answer 3

a fraction of the circumference of a circle.

Question 4

Arc Length Corollary

Answer 4

in a circle, the ratio of the length of a given arc AB to the circumference is equal to the ratio of the measure of the arc to 360 degrees. That is, Arc length of AB/2 x 3.14 = measure of arc AB/360 degrees, or Arc length of AB = 2 x 3.14 r measure of arc AB/360 degrees.

Question 5

Thm. 11.9 - Area of a Circle

Answer 5

the area of a circle is 3.14 times the square of the radius, or A=3.14r2.

Question 6

Sector

Answer 6

the region bounded by two radii of the circle and their intercepted arc.

Question 7

Thm. 11.10 - Area of a Sector

Answer 7

the ratio of the area A, of a sector to the area of its circle is equal to the ratio of the measure of the intercepted arc to 360 degrees.
A/3.14 r2 = measure of RQ/360 degrees, or A = measure of RQ/360 degrees times 3.14 r2.

Question 8

Segment of a Circle

Answer 8

a region bounded by a chord and its intercepted arc.