Find the value of the expression

The answer to your question is the letter C.

Step-by-step explanation:

Data

sin Ф = 1/5

cos Ф = ?

To solve this problem use trigonometric functions.

1.- The first condition is that the angle must be in the first quadrangle

(0° < Ф < 90°).

2.- Write the trigonometric function sine.

           sin Ф = Opposite side / hypotenuse   and sin Ф = 1/5

then, Opposite side = 1     hypotenuse = 5

3.- Use the Pythagorean theorem to find the adjacent side.

           Hypotenuse² = Opposite side² + Adjacent side²

-Solve for Adjacent side

            Adjacent side² = Hypotenuse² - Opposite sie²

-Substitution

            Adjacent side² = 5² - 1²

-Simplification

            Adjacent side² = 25 - 1

            Adjacent side ² = 24

            Adjacent side = √24

4.- Find the cosФ

             cos Ф = Adjacent side/hypotenuse

-Substitution

             cosФ = √24 / 5

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if you're asking about your rank, it depends on having a certain number of points and a certain number of brainliest answers. for example, at the time of this writing, i have 44338 points out of 15000 needed for the next (nearly triple the requirement! ) but i only have 24 out of 50 required brainliest answers. this number decays, meaning after a certain amount of time (i think about a month), the total number of brainliest answers you've earned doesn't count toward this total. (i've been stuck at the same rank for a long

the lesson to learn here is that you shouldn't worry about points or rank. chances are, no matter how good an answer you may provide, your efforts will go mostly unnoticed unless you focus on the newest/most active questions that get posted.

the answer to this is a. a^2 + b^2 = c^2