An arc is a part of the outside of a circle (a fraction of the circumference). A sector is a two-dimensional section of the whole circle (like a piece of pie). Use the applet below to explore how to calculate the measurements of these parts of a circle.
a. If a sector is formed by a 45° central angle, what fraction of the whole circle does it represent?[br]
b. Find the circumference of the whole circle. Leave your answer in terms of pi. If the arc is a fractional part of the whole circumference, can you use the fraction found above to find the length of the arc?
c. Find the area of the whole circle. Leave your answer in terms of pi. If the sector is a fraction of the whole circle, can you use the fraction found above to find the area of the sector?
d. Try 1 other central angle measurement and go through parts a-c again. Type your answers below. Label your answers as a., b., and c. :)
e. Try to create a formula for finding the length of an arc with any central angle.
f. Try to create a formula for finding the area of a sector with any central angle.