Answer:
approximately 36.633 cm if you use pi = 3.14
approximately 36.6519 cm if you use the calculator's stored value of pi
Work Shown:
L = arc length, r = radius, x = central angle in degrees
L = (x/360)*2*pi*r
L = (300/360)*2*pi*7
L = (35/3)pi .... exact arc length in terms of pi
L = (35/3)*3.14
L = 36.633 .... approximate arc length
Keep in mind that I used pi = 3.14 which isn't that great an approximation for pi. If you want to use more digits of pi, then use your calculator's built in version of it to get (35/3)*pi = 36.6519; of course it will depend on which option your teacher prefers.