Log (5) + log (3) = log (15)
(i) Angle AOC would equal 48°, as it is vertically opposite to angle DOB and they are therefore equal.
(ii) Angle DOE would equal 42°. We can see this because angles on a straight line add up to 180°, and 90 + 48 = 138, so we can do 180 - 138 = 42°.
I hope this helps!
3,989.237
A thousandth = 1/1000 = 0.001
Round 4th decimal place = 5
5 and over is rounding up and under 5 rounds down so it would be 3,989.237