[tex]$\triangle ZAP$[/tex] is a right triangle with right angle at [tex]$A$[/tex] and [tex]$\sin Z = \frac{4}{5}$[/tex]. What is [tex]$\cos P$[/tex]?

A. [tex]$\frac{3}{5}$[/tex]
B. [tex]$\frac{5}{4}$[/tex]
C. Not enough information
D. [tex]$\frac{4}{5}$[/tex]



Answer :

To determine [tex]\(\cos P\)[/tex] in the right triangle [tex]\(\triangle ZAP\)[/tex] with right angle [tex]\(A\)[/tex] and [tex]\(\sin Z = \frac{4}{5}\)[/tex], we can use the properties of right triangles and trigonometric identities.

1. Recognize the relationship involving sine:
[tex]\(\sin Z = \frac{\text{Opposite side to } Z}{\text{Hypotenuse}}\)[/tex]. Given [tex]\(\sin Z = \frac{4}{5}\)[/tex], it means in [tex]\(\triangle ZAP\)[/tex], if we denote the sides relative to angle [tex]\(Z\)[/tex]:
- Opposite to [tex]\(Z\)[/tex] = 4
- Hypotenuse = 5

2. Find the adjacent side to [tex]\(Z\)[/tex] using the Pythagorean theorem:
[tex]\[ \text{Hypotenuse}^2 = (\text{Opposite side})^2 + (\text{Adjacent side})^2 \][/tex]
Substituting the known values:
[tex]\[ 5^2 = 4^2 + (\text{Adjacent side})^2 \][/tex]
[tex]\[ 25 = 16 + (\text{Adjacent side})^2 \][/tex]
[tex]\[ (\text{Adjacent side})^2 = 25 - 16 = 9 \][/tex]
[tex]\[ \text{Adjacent side} = \sqrt{9} = 3 \][/tex]

3. Calculate [tex]\(\cos Z\)[/tex]:
[tex]\[ \cos Z = \frac{\text{Adjacent side to } Z}{\text{Hypotenuse}} = \frac{3}{5} \][/tex]

4. Use the fact that in a right triangle, the sine of one acute angle is the cosine of the other:
Since [tex]\(\triangle ZAP\)[/tex] is a right triangle and [tex]\(A\)[/tex] is the right angle:
[tex]\[ P = 90^\circ - Z \][/tex]
Hence, [tex]\(\cos P = \sin Z\)[/tex].

Given [tex]\(\sin Z = \frac{4}{5}\)[/tex], we have:
[tex]\[ \cos P = \frac{4}{5} \][/tex]

Therefore, the value of [tex]\(\cos P\)[/tex] is [tex]\(\frac{4}{5}\)[/tex].

The correct answer is:
[tex]\[ \boxed{\frac{4}{5}} \][/tex]