Answer:
c=13
Step-by-step explanation:
12^2+5^2=c2
144+25=c2
169=c2
Then you would square root it to get
C6 greeting cards for $23.40
A. 13.5/3=4.5
B. 38.25/9=4.25
C. 23.4/6=3.9
d. 32.8/8=4.1