A baseline assessment for high school geometry could include the following topics:

1. Basic geometric shapes: Identify and name different types of polygons, including triangles, quadrilaterals, pentagons, hexagons, etc.

2. Angle relationships: Identify and classify different types of angles, such as acute, obtuse, right, straight, and vertical angles.

3. Triangle properties: Understand and apply properties of triangles, including the sum of interior angles, the Pythagorean theorem, and the triangle inequality theorem.

4. Congruence and similarity: Identify and apply properties of congruent and similar figures, including corresponding angles and sides.

5. Perimeter and area: Calculate the perimeter and area of various polygons, including triangles, rectangles, squares, and circles.

6. Circles: Understand and apply properties of circles, including radius, diameter, circumference, and area.

7. Transformations: Identify and perform translations, reflections, rotations, and dilations on geometric figures.

8. Coordinate geometry: Understand and apply the distance formula, midpoint formula, and slope formula to solve problems involving lines and points on a coordinate plane.

9. Volume and surface area: Calculate the volume and surface area of three-dimensional figures, including prisms, pyramids, cylinders, cones, and spheres.

10. Proofs: Understand and construct geometric proofs using deductive reasoning and properties of geometric figures.

These topics cover the fundamental concepts and skills in high school geometry and can serve as a starting point for assessing students’ knowledge and understanding in the subject.