Cos = adjacent / hypotenuse
cos B = 4/5
B = cos^-1 (4/5)
B = 36.869897....
B = 36.87° (nearest hundredth)
Angle B = 36.87°.
<span>simplify third eqn -2x+5y+2x=4
5y=4
y=4/5
substitute back to 1st n 2nd eqn n solve for x n z
-4x-4-z=18 and -2x-4-2z=12
simplify -4x-z=22 and -2x-2z=16
-4x-(-x-8)=22
-3x+8=22
x=-14/3
z=-10/3
y=4/5
</span>
To find the mean, you need to find the average. The equation that I used was 61(1)+64(3)+67(5)+70(6)+73(5) and then divided that total by the total number of 20.
The answer would be D) 68.5
