Question

the acute angles in a right triangle are $\theta$ and $phi$. if $sin phi = 0.25$, what is $cos \theta$? (1 point)
0.65
0.75
0.55
0.25

Explanation:

Step1: Relate acute angles in right triangle

In a right triangle, the sum of acute angles is $90^\circ$, so $\theta + \phi = 90^\circ$, which means $\theta = 90^\circ - \phi$.

Step2: Apply co-function identity

Use the identity $\cos(90^\circ - \phi) = \sin\phi$. Substitute $\theta = 90^\circ - \phi$, so $\cos\theta = \sin\phi$.

Step3: Substitute given value

We know $\sin\phi = 0.25$, so $\cos\theta = 0.25$.

Answer:

0.25