First, we calculate the volume of the rectangular prism:
Volume of rectangular prism = width x height x base length
Volume of rectangular prism = 10 inches x 12 inches x 8 inches
Volume of rectangular prism = 960 cubic inches
Next, we calculate the volume of one of the triangular prisms:
Volume of one triangular prism = (1/2) x base length x perpendicular height x base length
Volume of one triangular prism = (1/2) x 8 inches x 6 inches x 8 inches
Volume of one triangular prism = 192 cubic inches
Since there are two triangular prisms on the top of the dollhouse, we need to calculate the total volume of both:
Total volume of the two triangular prisms = 192 cubic inches + 192 cubic inches
Total volume of the two triangular prisms = 384 cubic inches
Finally, we find the total volume of the dollhouse by adding the volume of the rectangular prism and the total volume of the two triangular prisms:
Total volume of the dollhouse = 960 cubic inches + 384 cubic inches
Total volume of the dollhouse = 1344 cubic inches
So, the expression for the total volume of the dollhouse is 1344 cubic inches.