Answer: 109.1 degrees
Step-by-step explanation:
To find the angle between the given vectors, we will use the formula below:
Cos(θ) = (U.V)/ |U|.|V|
Where
U = 13i - 8j
V = 2i + 9j
U.V = (2x13) + (-8×9)
U.V = 26 - 72
U.V = - 46
|U| = sqrt ( 13^2 + 8^2)
= sqrt ( 233) = 15.264
|V| = sqrt( 2^2 + 9^2)
= sqrt ( 85 ) = 9.22
Substitute all the value of the parameters into the formula
Cos ø = -46 / (15.3 × 9.2)
Cos ø = - 46 / 140.72
Cos Ø = - 32687
Find the cos inverse of the value
Ø = cos^-1( -32687)
Ø = 109.079 degrees
Therefore, the angle between the given vectors to the nearest tenth of a degree is 109.1 degrees
<u>Given</u>:
The given figure shows the intersection of the two lines.
The angles formed by the intersection of the two lines are (3x - 8)° and (2x + 12)°
We need to determine the equation to solve for x and to find the value of x.
<u>Equation to solve for x:</u>
Since, the two angles (3x - 8)° and (2x + 12)° are vertically opposite angles and the vertical angles are always equal.
Hence, we have;

Thus, the equation to solve for x is 
<u>Value of x:</u>
The value of x can be determined by solving the equation 
Thus, we have;


Thus, the value of x is 20.
A = 8B
A + B = 180
8B + B = 180
9B = 180
B = 20
A = 8 * 20 = 160
78.5= (3.14)r^2
25=r^2
5=r
So, the radius of a circle with an area is 78.5 cm^2 is 5 cm^2
Let the number be X. Then we find
7X + 3 = 39 - 2X
Now we collect the terms and find
9X = 36
Finally we divide by 9
X = 4
So our answer is 4