Question

Consider circle H with a 3 centimeter radius. If the length of minor arc RT is
2
3
π, what is the measure of ∠RST?
A) 20°
B) 30°
C) 40°
D) 60°
http://www.usatestprep.com/modules/gallery/files/173/17316/17316.JPG

Answer 1

RT is what length?

Answer 2

2/3

Answer 3

the arc RT is the same measure as the center angle that spans that arc

Answer 4

the chords form an angle with the vertex on the circle, and that angle is half the arc value on the circle

Answer 5

So what would be the measure of RST..?

Answer 6

that is for arc with angle measure,

for here, recall S=r*theta

Arc Distance = radius * center angle

Answer 7

is that 2/3 distance , or 2/3 pi measure, looks like a pi is in there

Answer 8

2/3 pi

Answer 9

so an angle , then the center angle is the same and the other the want is half of that

1/3 pi ---- pi/3 rad,

Answer 10

60 deg

Answer 11

here a reference thing for this type

http://www.regentsprep.org/Regents/math/geometry/GP15/CircleAngles.htm