Since the base is a regular quadrilateral, each of its 4 sides must have length
s = P/4
s = (60 cm)/4 = 15 cm
The area of one lateral face is the product of side length and height.
A = s×h
105 cm² = (15 cm)×h
Then the height of the prism is
h = (105 cm²)/(15 cm) = 7 cm
The area of the base is then
B = s²
B = (15 cm)² = 225 cm²
The volume of the prism is the product of its base area and height.
V = Bh
V = (225 cm²)×(7 cm) = 1575 cm³
The volume is 1575 cm³.