What is the formula for prism​

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

Ineed i been stuck on this question since yesterday

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie