Given: JL-tangent, LE-secant
Prove: LU·LE = LV·LK

Explanation:
By the properties of secants and tangents, ...
LU·LE = LJ²
LV·LK = LJ²
By the transitive property of equality, ...
LU·LE = LJ² = LV·LK
LU·LE = LV·LK