Answer:
57.5 degrees
Step-by-step explanation:
Assuming this is a triangle
a is adjacent is ∠B
b is opposite of ∠B
Use the inverse tangent equation: 
This equals to 57.52880771
<h2>
Answer:</h2>
Variance
<h2>
Step-by-step explanation:</h2>
The standard deviation is related to the variance. The standard deviation measures the variation or dispersion of a set of data and is represented by the Greek letter sigma
, while the variance measures how far a set of numbers are spread out from their average value. The variance is obtained by squaring the standard deviation, so the variance can be found as 
Answer:
First brand of antifreeze: 21 gallons
Second brand of antifreeze: 9 gallons
Step-by-step explanation:
Let's call A the amount of first brand of antifreeze. 20% pure antifreeze
Let's call B the amount of second brand of antifreeze. 70% pure antifreeze
The resulting mixture should have 35% pure antifreeze, and 30 gallons.
Then we know that the total amount of mixture will be:

Then the total amount of pure antifreeze in the mixture will be:


Then we have two equations and two unknowns so we solve the system of equations. Multiply the first equation by -0.7 and add it to the second equation:



+

--------------------------------------



We substitute the value of A into one of the two equations and solve for B.


Answer:
-1.5
Step-by-step explanation:
- 2 (y-2) = 4y + 8 - 2 (-4y - 3)
- 2y-4=4y+8+8y+6
- 2y-4=12y+14
- -4-14=14y-2y
- -18=12y
- y=-18/12
- y=-1.5
Answer:
21=x ( alternate angles are equal)