The answer is obtuse
a = 4
b = 28
c = 31
If a² + b² > c² - the angle is acute
If a² + b² < c² - the angle is obtuse
If a² + b² = c² - the angle is right
a² + b² = 4² + 28² = 16 + 784 = 800
c² = 31² = 961
800 < 900
a² + b² < c²
Therefore, the angle is obtuse
Since the population is going to increase by a certain percentage, we have to add 
to the percentage to keep the original population.
Now, convert the percentage into a decimal. You can do this by moving the decimal place two places to the left.
Now, just multiply that by 
.
It's impossible for 2 factors of 12 to add up to 16. So there would be no answer to that.
Answer: Choice A. (8, 4)
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Explanation:
Because x = 2y, we can replace every copy of x with 2y
Let's do so in the second equation
3x - 4y = 8
3(x) - 4y = 8
3(2y) - 4y = 8 .... x replaced with 2y; now let's isolate y
6y - 4y = 8
2y = 8
y = 8/2 ..... divide both sides by 2
y = 4
Use this y value to find x
x = 2y
x = 2*4
x = 8
So we have x = 8 and y = 4 pair together to get the answer (x,y) = (8, 4) which is choice A.
