Find the length of arc AB to the nearest tenth of a unit.

A. 62.8 units
Incorrect. Remember to multiply by 60/360 or 1/6. Try again.

B. 5.2 units
Incorrect. Remember to either use the diameter or multiply the radius by 2 in the circumference formula. Try again.

C. 52.4 units
Incorrect. This looks like the area of the sector. Try again.

D. 10.5 units
Correct!

The diameter of the circle is 15 meters. Find the length of the arc from P to Q, to the nearest tenth of a meter, for the portion of the circle that is NOT shaded.

A. 13.1 m
Incorrect. Check the question; find the portion of the circle that is NOT shaded. Try again.

B. 17.0 m
Incorrect. The circumference formula is 2rπ or dπ. Try again.

C. 34.0 m
Correct!

D. 1500.0 m
Incorrect. To find the arc length, divide the measure of the angle by the degrees in a circle and then multiply by the circumference. Try again.

Find the circumference of the circle in terms of π.

1. 3π in
   Incorrect. To find the circumference, set up the proportion, the measure of the angle over the degrees in a circle equals the arc length over the circumference. Find the cross product and solve. Try again.
2. 18π in
   Correct!
3. 9π in
   Incorrect. To find the circumference, set up the proportion, the measure of the angle over the degrees in a circle equals the arc length over the circumference. Find the cross product and solve. Try again.
4. 2160π in
   Incorrect. To find the circumference, set up the proportion, the measure of the angle over the degrees in a circle equals the arc length over the circumference. Find the cross product and solve. Try again.

Find the measure of the central angle of the shaded region or the sector.

1. 90°
   Incorrect. To find the measure of the angle write the proportion, measure of angle over measure of circle equals arc measure over the circumference and solve. Try again.
2. 160°
   Incorrect. Remember, the circumference formula is 2rπ or dπ. Try again.
3. 288°
   Incorrect. The picture shows an angle less than 90°. To find the measure of the angle write the proportion, measure of angle over measure of circle equals arc measure over the circumference and solve. Try again.
4. 80°
   Correct!