HELPPP. Find the line that has the mistake?

Interest begins accruing the date of the transaction except for auto loans mortgages credit card cash advances credit card purchases

Ineed the solution to this problem and the steps.

In the right triangular prism below, bg ⊥ fc. the volume of the prism is 900 cubic centimeter the height of the prism is 15 centimeters and the height of the triangular base is 10 centimeters. what is your he length of edg fc