Question

Consider circle H with a 5 centimeter radius. If the length of major arc RT is

25/3π, what is the measure of ∠RST?
A) 15°
B) 25°
C) 30°
D) 45°

Answer 1

C) 30°

Explanation:

s = 2πr x

n°

360°

n° =

360s

2πr

=

360(

25π

3

)

2π(5)

= 300

thus, ∠H = 360 - 300 = 60

then,

∠RST =

1

2

∠H =

1

2

60 = 30

Answer 2

Given the major arc and the minor arc share the same chord, the the angle RST will be:
∠RST=1/2∠RHT
∠RHT=1/3π=1/3×180=60
hence
∠RST=1/2×60=30°

C] Answer: 30°