The interest on the investment when the interest rate is 9% is; $101.25.
<h3>What is the interest when the interest rate is 9%?</h3>
It follows from the task content that the interest on an investment varies directly as the rate of interest.
Hence, it follows from proportion that the interest when the interest rate is; 9% can be calculated as follows;
= 9 ×45/4
= $101.25
Ultimately, the interest on the investment evaluated by means of proportional reasoning is therefore; $101.25.
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