Consider circle H with a 3 centimeter radius. If the length of minor arc RT is 2/3π, what is the measure of ∠RST? ​

The circumference of the whole circle =  2pi * 3 = 6 pi cm

So

2/3 pi / 6pi =     measure of angle RHT / 360

2/18 = 1/9 =  measure of angle RHT /360

360 (1/9) =  measure of angle RHT

40° =   measure of angle RHT

And angle RST is an inscribed angle = 1/2 RHT  =  20°