To find the power of 10 that makes the equation \( 2.103 \times 10^? = 210,300,000 \) true, we can start by expressing \( 210,300,000 \) in scientific notation.
We can write \( 210,300,000 \) as:
\[ 210,300,000 = 2.103 \times 10^8 \]
Now, we have the equation:
\[ 2.103 \times 10^? = 2.103 \times 10^8 \]
Since the coefficients \( 2.103 \) on both sides are equal, we can equate the powers of 10:
\[ ? = 8 \]
Therefore, the power of 10 that makes the equation true is:
\[ \boxed{8} \]