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Solid Geometry (Advanced)

Harder items at competition-adjacent depth.

Phase 2 · Gaokao

Solid Geometry: core idea

Composite solids.

Example problem: hint and answer

Volume by washers: rotate y=xy=x, 0..10..1 about xx-axis /π/\pi?

Hint: Disk. Answer: 1/3.

Practice (9 problems — type your answers)

  • 1. Skew lines in cube opposite edges: distance if edge 22?

  • 2. Sphere ∩ plane through center: circle radius if sphere r=5r=5?

  • 3. Optimize cylinder in sphere r=Rr=R: max volume cylinder height? For R=3R=\sqrt3: height?

  • 4. Truncated cone volumes — r=2,R=4,h=6r=2,R=4,h=6: volume /π/\pi?

  • 5. Rotate y=xy=\sqrt{x} 0..10..1 about yy-axis: volume /π/\pi (shells)?

  • 6. Dihedral of cube adjacent faces degrees?

  • 7. Vector: volume parallelepiped edges ⟨1,0,0⟩,⟨0,1,0⟩,⟨0,0,2⟩\langle1,0,0\rangle,\langle0,1,0\rangle,\langle0,0,2\rangle?

  • 8. Prove right angle: vectors ⟨1,0⟩,⟨0,1⟩\langle1,0\rangle,\langle0,1\rangle dot?

  • 9. Cross section triangle prism: equilateral side 22 area?

Solid Geometry Practice Problems — Advanced