what is the lateral surface area of the solid (options in picture) please help!

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Explanation:
The base faces are the two triangles that are parallel to one another. We'll be ignoring those faces when computing the lateral surface area.
Instead, we focus on the three rectangles that form the sides. We can think standing the prism on one of the triangular faces, so that one triangle is the floor and the other triangle is the ceiling. The rectangular pieces are the walls of this room.
The three areas then combine to 128+96+96 = 320 square cm which is the lateral surface area.
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As a different approach, we can use this formula
LSA = p*h
where LSA is the lateral surface area, p is the perimeter of the base polygon, h is the height of the prism.
The base triangle has sides of 8, 6 and 6. So the perimeter is p = 8+6+6 = 20 cm. The height is h = 16 cm. The LSA is therefore,
LSA = p*h = 20*16 = 320 square cm.