Answer:
C=12.8
On the caculator there are two buttons you need to press. 2nd and then x2. Once you press those add in 20.
You get 4.47 ROUND THAT to 4.5
12(2)+4.5(2)=C(2)
12×12=144 4.5×4.5=20.25
144+20.25=164.25
164.25=C(2)
On the caculator press 2nd and then x2
12.81=12.8
C=12.8
