The effective rate is calculated in the following way:

where r is the effective annual rate, i the interest rate, and n the number of compounding periods per year (for example, 12 for monthly compounding).
our compounding period is 2 since the bank pays us semiannually(two times per year) and our interest rate is 8%
so lets plug in numbers:
Answer:
19.4 %
Step-by-step explanation:
The formula for<em> return on assets</em> (ROA) is
ROA = Net income /Total assets × 100 %
Since assets vary, we use the <em>average</em> of the total assets over the period.
<em>Calculate the average total assets</em>
At beginning of year, total assets = $263 000
At end of year, total assets = $313 000
Average = (313 000 + 263 000)/2
Average = 576 000/2
Average = $288 000
===============
<em>Calculate the ROA</em>
Net income = $56 000
ROA = 56 000/288 000 × 100 %
ROA = 0.194 × 100 %
ROA = 19.4 %
The company’s return on assets is 19.4 %.
First we'll substitute
with 

Then we can separate this.

Then we'll solve this.



Then we'll plug in to find the extraneous solutions (if any)

Supplementary angles add to 180
4+5=9
180/9=20
4*20=80
5*20=100
the angles are 80 degrees and 100 degrees