When you're rounding to the nearest thousandth, you are rounding to the third decimal place. If you take a look at the fourth decimal place, it is a 0, meaning that you do not have to round the third decimal place up. Therefore, this number rounded to the nearest thousandth is simply 5.804. Hope this helps!
After the thousands place is a 0, so the number for the thousands place would stay the same. If it were higher than 4, it would round to 5.805 (but it isnt so it's 5.804)
To find the area of a composite figure, separate the figure into simpler shapes whose area can be found. Then add the areas together. Be sure than none of the simpler figures have overlapping areas
