How to define a circle and identify its main parts.
How to use the principle that corresponding parts of congruent triangles are congruent, or CPCTC.
How to relate corresponding altitudes, medians and angle bisectors in similar triangles.
How to label the parts of a prism, how to distinguish between an oblique and a right prism.
How to describe the unit circle. How to draw the unit circle and label its parts. How to strategize about finding coordinates on the unit circle.