FTCE General Knowledge Math Practice Test 2026 – All-in-One Guide to Ensure Exam Success!

The variable 'r' commonly represents the radius of a solid in mathematical formulas, particularly those related to circles and spheres. It denoted half the distance across a circular cross-section, and it is used in calculations for the area of a circle (A = πr²) and the volume of a sphere (V = (4/3)πr³). Understanding the role of 'r' as the radius is essential when working with geometric formulas, as it directly influences measurements of both surface area and volume of solids.