E.MATH CHAP 9 arc length, sector areas and radian measure completed:

E.MATH CHAP 9 arc length, sector areas and radian measure completed:

1. 9.1: ARC LENGTHS:

   • chord = line segment with end pts on a circle. divides circle into 2 parts(segments)
     • larger part is called MAJOR SEGMENT
     • smaller part is called MINOR SEGMENT
   • circle can also be divided into 2 parts(sectors) by 2 radii
   • arc length = (0 / 360) x (2 x pi x r)

2. 9.2: SECTOR AREAS AND SEGMENT AREAS:

   • area of sector = (0/360) x ( pi x r )

3. 9.3: RADIAN MEASURE

   • 1 rad = measure of an angle SUBTENDED at the CENTRE OF THE CIRCLE BY AN ARC EQUAL IN LENGTH TO THE RADIUS
   • pi radian = 180 degrees

4. 9.4: FORMULAE IN RADIAN MEASURE:

   • arc length (in radian) = r 0
   • area of sector = (1/2) x (r^2) x 0
   • 0 (theta) is in radian