How do you find the value of x in. x+y=z

If the value of cos330°is√3/2 then find cos 165°.

From the top of a tree a bird looks down on a field mouse at an angle of depression of 50°. if the field mouse is 40 meters from the base of the tree, find the vertical distance from the ground to the bird's eyes.

Lana's family entered a 5-kilometer race lana's average step length is about 0.5 meter how many steps will she need to take the finish