Answer:
Value of
Step-by-step explanation:
Given: A vertical line is dropped from the x-axis to the point (12, -9) as shown in the diagram below;
To find the value of
.
By definition of secants;
![\sec \theta = \frac{1}{\cos \theta}](https://tex.z-dn.net/?f=%5Csec%20%5Ctheta%20%3D%20%5Cfrac%7B1%7D%7B%5Ccos%20%5Ctheta%7D)
Now, first find the cosine of angle ![\theta](https://tex.z-dn.net/?f=%5Ctheta)
As the point (12 , -9) lies in the IV quadrant , where ![\cos \theta > 0](https://tex.z-dn.net/?f=%5Ccos%20%5Ctheta%20%3E%200)
Consider a right angle triangle;
here, Adjacent side = 12 units and Opposite side = -9 units
Using Pythagoras theorem;
![(Hypotenuse side)^2= (12)^2 + (-9)^2 = 144 + 81 = 225](https://tex.z-dn.net/?f=%28Hypotenuse%20side%29%5E2%3D%20%2812%29%5E2%20%2B%20%28-9%29%5E2%20%3D%20144%20%2B%2081%20%3D%20225)
or
![Hypotenuse = \sqrt{225} =15 units](https://tex.z-dn.net/?f=Hypotenuse%20%3D%20%5Csqrt%7B225%7D%20%3D15%20units)
Cosine ratio is defined as in a right angle triangle, the ratio of adjacent side to hypotenuse side.
![\cos \theta = \frac{Adjacent side}{Hypotenuse side}](https://tex.z-dn.net/?f=%5Ccos%20%5Ctheta%20%3D%20%5Cfrac%7BAdjacent%20side%7D%7BHypotenuse%20side%7D)
then;
![\cos \theta = \frac{12}{15} = \frac{4}{5}](https://tex.z-dn.net/?f=%5Ccos%20%5Ctheta%20%3D%20%5Cfrac%7B12%7D%7B15%7D%20%3D%20%5Cfrac%7B4%7D%7B5%7D)
and
therefore, the value of
is,