Question

If $\sin {50}^o=0.766$, the value of $\sec {40}^{\circ }$ is

• A. $1$
• B. $.766$
• C. $\frac{1}{.766}$
• D. $0$

Answer 1

The correct option is C $\frac{1}{.766}$

Since, $\sin {50}^o=0.766$
And from figure $\sin {50}^o=\frac{AB}{AC}$
Also, $\sec {40}^o=\frac{AC}{AB}$
Hence, $\sec {40}^o=\frac{1}{0.766}$