Question

If a vertical line is dropped from the x-axis to the point (12, –9) in the diagram below, what is the value of sec?

Answer 1

Answer:

Value of $\sec \theta = \frac{5}{4}$

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 $\sec \theta$.

By definition of secants;

$\sec \theta = \frac{1}{\cos \theta}$

Now, first find the cosine of angle $\theta$

As the point (12 , -9) lies in the IV quadrant , where $\cos \theta > 0$

Consider a right angle triangle;

here, Adjacent side = 12 units and Opposite side = -9 units

Using Pythagoras theorem;

$(Hypotenuse side)^2= (12)^2 + (-9)^2 = 144 + 81 = 225$

or

$Hypotenuse = \sqrt{225} =15 units$

Cosine ratio is defined as in a right angle triangle, the ratio of adjacent side to hypotenuse side.

$\cos \theta = \frac{Adjacent side}{Hypotenuse side}$

then;

$\cos \theta = \frac{12}{15} = \frac{4}{5}$

and

$\sec \theta = \frac{1}{\cos \theta}= \frac{1}{\frac{4}{5}} = \frac{5}{4}$

therefore, the value of $\sec \theta$ is, $\frac{5}{4}$

Answer 2

Answer:

B

Step-by-step explanation:

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