Respuesta :

mikaylachelene
Radius = Diameter /2 

So, Radius = 8.4/2 or 4.2 

4.2^2 = 17.64. 

17.64 x pi = 55.39 sq cm. 

cm because we are being consistent with the units of measurement already in use.
musiclover10045

area of a circle = PI x r^2

r = 8.4/2 = 4.2

using 3.14 for PI

 area = 3.14 x 4.2^2 = 55.3896 square cm

 round answer as needed