A radio transmission tower is 200 feet high. How long should a guy wire be if it is to be attached to the tower 10 feet from the top and is to make an angle of 21 degrees with the ground?
Draw a picture mate...draw a line depicting the tower vertically and label it as 200feet high, then make a right angled triangle, with the hypotenuse representing the guy wire and the horizontal line representing the ground.
Now since the wire is connected 10 feet from the top of the tower the triangle you really have has a height of 190 feet, a hypotenuse of length 'x' (what you're trying to find) and the angle the wire makes with the ground is 21 degrees. From this, which trig. ratio (sin, cos, tan) allows you to relate the side opposite the angle (from the picture) to hypotenuse?