This document contains mathematical formulas relating different variables such as radius, temperature, pressure, and distance. It provides 25 equations showing relationships between variables using proportionality constants, including equations for surface area of a sphere, torque, force, price, and others. The document demonstrates different proportional relationships between physical quantities.

2. Variation
1. R = kD 3. S = kT 5. T = kP 7. A = kr2 9. C = kD3 11. T = kD
13. S = kT 15. T = kP 17. A = kr2 19. m = k/s2
21. F = k/T 23. N = k/p, N = 1350/p, if N = 10, then p = 135($/per marble)
25. p = kr2, p = 11r2/72, if r = 12, p ≈$12.38.
Variation