circle unit formulas and definitions:

Question 1

What is the formula for circumference?

Answer 1

2 x pi x radius or d x pi

Question 2

What is the formula for the arc length?

Answer 2

measure of the arc/360 times the circumference

Question 3

What is the formula for the area of a circle?

Answer 3

pi x radius squared

Question 4

What is the formula for the area of a triangle?

Answer 4

b times h/2

Question 5

What is the formula for the area of
a polygon?

Answer 5

Apothen x perimeter/2

Question 6

How do you find the area of a segment?

Answer 6

Area sector - area triangle

Question 7

How do you find the area of a shaded region?

Answer 7

Area of the circle - area segment

Question 8

What is the annulus?

Answer 8

The region between two concentric circles

Question 9

What are concentric circles?

Answer 9

Coplanar circles that have the same center

Question 10

What are coplanar circles?

Answer 10

Circles in the same plane

Question 11

What is a central angle?

Answer 11

An angle whose vertex lies on the center of the circle

Question 12

THEOREM: The measure of an angle formed by two lines that intersect outside a circle is half the difference of the measures of the intercepted arcs. What is the formula?

Answer 12

Big arc - smaller arc/2

Question 13

THEOREM: The measure of an angle formed by two lines that intersect inside a circle is half the sum of the measures of the intercepted arcs. What is the formula?

Answer 13

Arc 1 + arc 2/2

Question 14

What is the equation formula for a circle?

Answer 14

( x - h )^2 + ( y - k )^2 = r^2