Answer:

Explanation:
For this problem, let's find the surface area of each body and then add them.
1. Surface area of the rectangular prism (red color body):
Formula:
; where w is width, w is height, and l is length.
a) Annotate the values.
l= 12
h= 3
w= 4
b) Substitute in the formula and calculate.

2. Surface area of the triangular prism (blue color body):
For this one we are gonna work part by part.
a) Let's calculate the area of the 2 triangular sides first.
Area of a triangle:
; where b is base and h is height is the triangle.

Note: we mltiply by 2 because there are 2 sides with this shape in the body.
b) Area of the back side that touches the rectangular prism.
This part is just a rectangle, hence, it's area formula is:

c. Area of the plane that forms a slope.
Is basically another rectangle, hence:

d. Area of the part next to the text "5 cm":
Is basically another rectangle, hence:

e. Now, the total surface area of this rectangular prism should be the addition of all it's partial areas:

3. Surface area of the composite figure:
