The answer is B-about 18km
This is because you round 18.23 to 18km
then you round 13.94 to 14km
you add these rounded numbers together
you take it away from 50km
the answer would then me 18km
but it be ABOUT because that was only a rough estimate because it was rounded
Length x Width = Area
In your case, you'd want to flip around the equation.
100+x=900
900 divided by 100 is 9, so your width would be 9 Yards.
Sum of angles in a triangle is 180 degrees.
2x + 2x + 8x = 180
12x = 180
x = 180/12 = 15
Therefore, the smallest angle mmeasures 2(15) = 30 degrees.
In order to do this we need to make them both fractions, or both decimals. It's much easier to make them both decimals, as you can get

into decimal form by simply dividing 1 by 5.

If 1/5 = .20, then 1/5 is greater than .15!
To the nearest what the nearest ten is 360,000 nearest ten thousand 400,000