To determine how many times greater \( 2.523 \times 10^{-4} \) is than \( 2.9 \times 10^{-8} \), we can divide the two numbers:
\[ \text{Factor} = \frac{2.523 \times 10^{-4}}{2.9 \times 10^{-8}} \]
We can split this division into two parts: the coefficients and the powers of ten:
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Dividing the coefficients: \[ \frac{2.523}{2.9} \approx 0.869 \]
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Dividing the powers of ten: \[ 10^{-4} \div 10^{-8} = 10^{-4 - (-8)} = 10^{-4 + 8} = 10^{4} \]
Now, we can combine these two results:
\[ \text{Factor} \approx 0.869 \times 10^{4} \]
Next, we convert \( 0.869 \) into scientific notation. Since \( 0.869 = 8.69 \times 10^{-1} \), we can rewrite the factor:
\[ \text{Factor} \approx 8.69 \times 10^{-1} \times 10^{4} = 8.69 \times 10^{3} \]
Rounding \( 8.69 \) to two significant digits gives us \( 8.7 \):
Thus, the final result is:
\[ \text{Factor} \approx 8.7 \times 10^{3} \]
Therefore, the answer is:
\[ \boxed{8.7 \times 10^{3}} \]