Answer:
140 cm²
Explanation:
You want the total surface area of a triangular prism as represented by the given net.
Area
The total area is the sum of the areas of the two triangular bases and the three rectangular faces. The relevant formulas are ...
A = 1/2bh . . . . . . area of triangle with base b, height h
A = bh . . . . . . . area of rectangle with base b, height h
Application
The total area is ...
SA = 2(1/2bh) +(b1)h +(b2)h +(b3)h . . . . . . . triangle h=5, rectangle h=8
SA = 2(1/2)(4 cm)(5 cm) + (8 cm)(6 cm +4 cm +5 cm)
= 20 cm² +(8 cm)(15 cm)
= 140 cm²
The total surface area of the triangular prism is about 140 cm².