Question

If `cos theta=4/5`, `0<=theta=<pi/2`, how do you find `sin theta`?

Answer 1

`color(green)(sin(theta)=3/5`

Explanation:

`cos="adjacent"/"hypotenuse"color(white)("XXXXX")sin="opposite"/"hypotenuse"`

By the Pythagorean Theorem
`color(white)("XXX")"opposite" = sqrt(5^2-4^2)=3`

`rArr sin(theta)=3/5`