The volume is given by: V = A * H Where, A: area of the base H: prism height Clearing the area we have: A = V / H A = 276/10 A = 27.6 feet ^ 2 The area of the base is given by: A = (1/2) * (b) * (h) Where, b: base of the triangle h: height of the triangle Clearing b we have: b = (2 * A) / (h) Substituting values: b = (2 * 27.6) / (6.9) b = 8 feet Answer: the base length is: b = 8 feet