RT = 6.3 units and RV = 13.1 units. What is TV?

RT = 6.3 The rule is you can do any valid operation on both sides of an equation and it will still be equal. Divide by R.
T = 6.3/R

RV = 13.1 Same again.
V = 13.1/R

TV = 6.3/R x 13.1/R = 82.53/R^2