Answer:
radius was divided by 2
Explanation:
A circle that originally had a circumference of 31.4 cm, now has a circumference of 15.7 cm
Circumference of a circle formula =

where 'r' is the radius of a circle
circumference of 31.4 cm
31.4 =

the value of pi is 3.14
31.4 =

divide both sides by 3.14 *2
r=5
circumference of 15.7 cm.
15.7 =

the value of pi is 3.14
15.7 =

divide both sides by 3.14

Originally the radius = 5 cm and now the radius is 2.5 cm
It was divided by 2