Answer:
42.7
Step-by-step explanation:
Formula for Circumference of a circle is C=2πr
π=3.14
radius/r=6.8
C= 2*3.14*6.8
C=42.704
Round to 42.7
42.73
2*pi*r = 2*pi*6.8=42.73
k = 21
X=15