## Elementary Geometry for College Students (7th Edition)

cos α = $\frac{b}{c}$ sin β = $\frac{b}{c}$ Thus cos α = sin β
Lets take question 1 diagram: as we know cos α = $\frac{adjacent}{hypotenus}$ for question 1 , cos α = $\frac{12}{13}$ sin β = $\frac{opposite}{hypotenus}$ for question 1 , sin β = $\frac{12}{13}$ Therefore we can say that cos α = sin β = $\frac{12}{13}$