adv math

For word problems they have 3 formulas that can be used to solve the equations
s=r x theta
k=1/2 r^2 x theta
k= 1/2 rs

these signs also have alternate meanings:
theta= apparent size
s=diameter of an object
r=distance between an object

ex:1

a sector of a circle has a radius of 8 cm and a central angle of 60 degrees. find its approximate arc length and area.
1st. list the formula
r=8cm theta=60 degrees
s=? k=? s=r x theta
2nd: plug in the formula
s=(8)(60)
s=140 degrees
3rd.plug in the formula to find k
k=1/2 x 8 x 140
k=560 cm