15.1k views
5 votes
What value of θ makes cosθ = sin70° a true statement?

A) 20°
B) 40°
C) 70°
D) 90°

User Sweepster
by
8.6k points

2 Answers

6 votes

Answer:

A

Explanation:

User Robare
by
7.1k points
3 votes

Answer:

A) 20°

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:


\sin\theta=\cos(90\°-\theta)


\cos\theta=\sin(90\°-\theta)

Given statement:


cos\theta=\sin70\°

Applying co-function complements


\cos\theta=\sin(90\°-\theta)

Since, we can represent 70° = 90°-20°

So


\cos20\°=\sin(90\°-20\°)

Thus,
\theta=20\° makes the statement true.

User Alexbclay
by
8.2k points

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