ANSWER
• A vertical plane that cuts through the top vertex, perpendicular to the base,: ,triangle
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• A horizontal plane, that cuts through the pyramid, parallel to the base:, ,square
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• A vertical plane that cuts through the base and two opposite lateral faces:, ,trapezoid
Step-by-step explanation
• A vertical plane that cuts through the top vertex, perpendicular to the base,: if we draw a rectangle perpendicular to the base that passes through the vertex,
Hence, the cross-sectional shape is a triangle.
• A horizontal plane, that cuts through the pyramid, parallel to the base:, if it is a plane parallel to the base, then it should have the same shape as the base,
Hence, the cross-sectional shape is a square.
• A vertical plane that cuts through the base and two opposite lateral faces:, again, we can draw this plane. The cross-sectional shape will have one pair of parallel sides and one pair of non-parallel sides,
Hence, the cross-sectional shape is a trapezoid.