Question

Given that $\cos {50}^o{20}^{\prime }=0.6388$ and $\cos {50}^o{42}^{\prime }=0.6334$, then the possible value of $\cos {50}^o{20}^{\prime }$ is

• A. $0.6293$
• B. $0.6307$
• C. $0.6361$
• D. $0.6414$

Answer 1

Answer: (C)

$0.6361$

$\cos \left({50}^0{18}^{\prime }\right)=0.6388$

$\cos \left({50}^0{42}^{\prime }\right)=0.6334$

The possible value of $\cos \left({50}^0{20}^{\prime }\right)$ must lie between $\cos \left({50}^0{18}^{\prime }\right)$ and $\cos \left({50}^0{42}^{\prime }\right)$. Thus the only possible value is $0.6361$