Answer:
Part a) [tex]SA=458.4\ cm^2[/tex]
Part b) Added only one side triangular face instead of three side triangular faces
Step-by-step explanation:
we know that
The surface area of a triangular prism is equal to two times the area of the base plus the area of its three triangular faces
so
[tex]SA=2(73.2)+3(104)[/tex]
[tex]SA=146.4+312[/tex]
[tex]SA=458.4\ cm^2[/tex]
Riley's error was
[tex]SA=2(73.2)+(104)=250.4\ cm^2[/tex]
added only one side triangular face instead of three side triangular faces