Question

Find the surface area of the composite solid.

Answer 1

Surface Area of the Composite Sold = SA of Rectangular Prism + SA Right Angled Triangular Prism.

Finding the Surface Area of the Rectangular Prism
A=2(wl+hl+hw)
= 2·(10·12+10·12+10·10)=680

SA Right Angled Triangular Prism:
Use a net to find the SA to see the shapes easier. You basically find the area of each face (A=bh and A=2(1/2bh)). You would get 360

680in^3 + 360in^3 = 1040in^3
The answer is D) 1040in^3

Answer 2

Option B is correct.

Explanation:

Given:

A Solid Figure made up pf cuboid and a triangular based prism.

To find: Total Surface area of the figure.

Total Surface Area = Area of front + Area of top + Area of Back + 2 × Area of side + Area of bottom

Area of Front = Area of Square + Area of rectangle

= 10 × 10

= 100 in.²

Area of top = Area of Rectangle

= 13 × 10

= 130 in.²

Area of back = Area of square in down + Area of rectangle in up

= 10 × 10 + 5 × 10

= 100 + 50

= 150 in.²

Area of the bottom = Area of the rectangle

= 12 × 10

= 120 in.²

Area of the side = Area of rectangle + Area of the triangle

= 12 × 10 + 1/2 × 5 × 12

= 120 + 5 × 6

= 120 + 30

= 150 in.²

Total Surface Area = 100 + 130 +150 + 120 + 2 × 150

= 500 + 300

= 800 in.²

Therefore, Option B is correct.