Answer:
30 marbles
Step-by-step explanation:
x = total # marbles
5/2 = x/12
2x = 60
x = 30
A
a^2 + 144^2 = 145^2
a^2 + 20736 = 21025
a^2 = 289
a = sqrt(289)
A,D
0.06$
is d and a