Answer:
The Value of c can be found using the formula 3c = 8.37. Each Baseball costs $2.79
Step-by-step explanation:
3c=8.37 divide 3c and 8.37 by 3 and it will tell you that c = 2.79.
You can use a tangent:

We have opposite = 17 and adjacent = x.

substitute:
cross multiply
multiply both sides by √3

divide both sides by 3

Use the Pythagorean theorem:

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Other method.
triangle.
The sides are in the ratio 
Therefore

14 days
.25 x 4days = $1.00
0.30x 10 days = $3.00
$3 + $1 = $4