Respuesta :
Answer:
A) 20°
Step-by-step explanation:
Sine and cosine are co-function complements which means that value of sine of an angle is equal to the value of cosine of the complementary angles.
This can be represented by:
[tex]\sin\theta=\cos(90\°-\theta)[/tex]
[tex]\cos\theta=\sin(90\°-\theta)[/tex]
Given statement:
[tex]cos\theta=\sin70\°[/tex]
Applying co-function complements
[tex]\cos\theta=\sin(90\°-\theta)[/tex]
Since, we can represent 70° = 90°-20°
So
[tex]\cos20\°=\sin(90\°-20\°)[/tex]
Thus, [tex]\theta=20\°[/tex] makes the statement true.
