Answer
sin α = $\frac{a}{c}$
cos β = $\frac{a}{c}$
thus sin α = cos β
Work Step by Step
Lets take question 1 diagram:
as we know sin α = $\frac{opposite}{hypotenus}$
for question 1 , sin α = $\frac{5}{13}$
cos β = $\frac{adjacent}{hypotenus}$
for question 1 , cos β = $\frac{5}{13}$
Therefore we can say that sin α = cos β = $\frac{5}{13}$
