Given:
The base of the triangle = 5 mm
The height of the triangle = 7 mm
The height of the prism = 12 mm
The other two sides of the triangle are = 9 mm and 9 mm
To find the surface area of the triangular prism.
Formula
The surface area of the triangular prism is
[tex]SA = bh+(s_{1} +s_{2} +s_{3})H[/tex]
Where,
b be the base of the triangle
H be the height of the prism
h be the height o the triangle
[tex]s_{1} ,s_{2} ,s_{3}[/tex] are the sides of the triangle.
Now,
Putting, b=5, h=7, H=12, [tex]s_{1}=5,s_{2} =9,s_{3} =9[/tex] we get,
[tex]SA = (5)(7)+(5+9+9)(12)[/tex] sq mm
or, [tex]SA = 35+276[/tex] sq mm
or, [tex]SA = 311[/tex] sq mm
Hence,
The surface area of the given prism is 311 sq mm.
