To simplify the expression \((15^6)^2\) using the Power Rule of Exponents, you multiply the exponents. The Power Rule states that \((a^m)^n = a^{m \cdot n}\).
Applying this to your expression:
\[ (15^6)^2 = 15^{6 \cdot 2} = 15^{12} \]
So, the equivalent expression is:
15^12