Answer:
65.56°
Step-by-step explanation:
We know that if we take dot product of two vectors then it is equal to the product of magnitudes of the vectors and cosine of the angle between them
That is let p and q be any two vectors and A be the angle between them
So, p·q=|p|*|q|*cosA
⇒
Given u=-8i-3j and v=-8i+8j


let A be angle before u and v
therefore, 
⇒
Therefore angle between u and v is 65.56°
In this sequence, we're given the first term, which is 45.
The difference between each term is -3, which means 3 will be subtracted in each term.
We're asked to find the value of the tenth term, and we can do so by using this formula:
a(n) = a(1) + d(n - 1)
Replace values.
a(10) = 45 + -3(9)
a(10) = 18
<h3>The value of the tenth term is 18.</h3>
First, make up some variables to represent the number of Girls and Boys in the choir.
B = number of boys
G = number of girls
You know that there are 4 times as many girls in the choir as boys. Therefore, the equation you can write is:

If you cross-multiply, then you get the simplified equation:
G = 4B
Intuitively this makes sense since if you multiplied the number of boys in the class by 4, that would be equal to the number of girls you have.
Now, we know that the total class size is 60. So girls plus boys equals 60:
G+B = 60
To solve the equation, replace the G in this equation with the replacement you found before, 4B.
G + B = 60 -->
4B + B = 60 -->
5B = 60 -->
B = 12
However, you are trying to find the number of girls, so plug the answer back into your equation.
G + B = 60 -->
G + 12 = 60 -->
G + 12 -12 = 60 - 12 -->
G = 48
The number of girls you have is 48.