a. Use the appropriate formula to find the value of the annuity.
b. Find the interest.
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(i) Click the icon to view some finance formulas.
a. The value of the annuity is $\mathrm{\$}$
(Do not round until the final answer. Then round to the nearest dollar as needed.)
b. The interest is $\mathrm{\$}$
(Use the answer from part (a) to find this answer. Round to the nearest dollar as needed.)

Step 1 ：Given the periodic deposit (P) is $120, the annual interest rate (r) is 4.5% or 0.045 in decimal form, the number of times interest is compounded per year (n) is 2, and the number of years (t) is 35.

Step 2 ：First, we calculate the future value of the annuity (FV) using the formula: $FV=P\times [(1+\frac{r}{n}{)}^{nt}-1]÷\frac{r}{n}$

Step 3 ：Substitute the given values into the formula: $FV=120\times [(1+\frac{0.045}{2}{)}^{2\times 35}-1]÷\frac{0.045}{2}$

Step 4 ：Calculate the future value to get: $FV=19984.75410998469$

Step 5 ：Round the future value to the nearest dollar to get: $FV=\mathrm{\$}19985$

Step 6 ：Next, calculate the total amount of deposits over the 35 years: $total\mathrm{\_}deposits=P\times n\times t=120\times 2\times 35=\mathrm{\$}8400$

Step 7 ：Finally, calculate the interest by subtracting the total deposits from the future value: $interest=FV-total\mathrm{\_}deposits=19985-8400=11584.75410998469$

Step 8 ：Round the interest to the nearest dollar to get: $interest=\mathrm{\$}11585$

Step 9 ：$\boxed{{\displaystyle \text{The value of the annuity is \$19985 and the interest is \$11585.}}}$