9514 1404 393
Answer:
159 cm² (see comment)
Step-by-step explanation:
The area of the central rectangle is ...
A = LW = (18 cm)(8 cm) = 144 cm² . . . rectangle area
The area of the two triangles is ...
A = 2(1/2bh) = bh = (6 cm)(2.5 cm) = 15 cm² (each triangle is 7.5 cm²)
So, the total area of the net shown is ...
144 cm² +15 cm² = 159 cm² . . . prism surface area
_____
Additional comment
Yet another poorly edited geometry problem. The equilateral triangle will have a height closer to 5.2 cm than 2.5 cm. Apparently, somebody transposed the figures. If the correct number is used, the single-triangle area is 15.6 cm² and the total area is 175.2 cm².
Which set of answers is "correct" will depend on whether the answer key matches the intended problem, or the problem actually shown.
