This subsection contains the propositions from Book 12 of Euclid's “Elements”.

- Proposition: Prop. 12.01: Areas of Similar Polygons Inscribed in Circles are as Squares on Diameters
- Proposition: Prop. 12.02: Areas of Circles are as Squares on Diameters
- Proposition: Prop. 12.03: Tetrahedron divided into Two Similar Tetrahedra and Two Equal Prisms
- Proposition: Prop. 12.04: Proportion of Sizes of Tetrahedra divided into Two Similar Tetrahedra and Two Equal Prisms
- Proposition: Prop. 12.05: Sizes of Tetrahedra of Same Height are as Bases
- Proposition: Prop. 12.06: Sizes of Pyramids of Same Height with Polygonal Bases are as Bases
- Proposition: Prop. 12.07: Prism on Triangular Base divided into Three Equal Tetrahedra
- Proposition: Prop. 12.08: Volumes of Similar Tetrahedra are in Cubed Ratio of Corresponding Sides
- Proposition: Prop. 12.09: Tetrahedra are Equal iff Bases are Reciprocally Proportional to Heights
- Proposition: Prop. 12.10: Volume of Cone is Third of Cylinder on Same Base and of Same Height
- Proposition: Prop. 12.11: Volume of Cones or Cylinders of Same Height are in Same Ratio as Bases
- Proposition: Prop. 12.12: Volumes of Similar Cones and Cylinders are in Triplicate Ratio of Diameters of Bases
- Proposition: Prop. 12.13: Volumes of Parts of Cylinder cut by Plane Parallel to Opposite Planes are as Parts of Axis
- Proposition: Prop. 12.14: Volumes of Cones or Cylinders on Equal Bases are in Same Ratio as Heights
- Proposition: Prop. 12.15: Cones or Cylinders are Equal iff Bases are Reciprocally Proportional to Heights
- Proposition: Prop. 12.16: Construction of Equilateral Polygon with Even Number of Sides in Outer of Concentric Circles
- Proposition: Prop. 12.17: Construction of Polyhedron in Outer of Concentric Spheres
- Proposition: Prop. 12.18: Volumes of Spheres are in Triplicate Ratio of Diameters