In the diagram, POQ is the diameter of the circle centre O. Calculate ∠QRS

In the diagram, POQ is the diameter of the circle centre O. Calculate ∠QRS

Answer Details

Since POQ is the diameter of the circle, we know that angle POR = 90 degrees. Therefore, angle QOR is also 90 degrees because it is vertically opposite to angle POR. Since QR is a chord of the circle, angle QRS is half of the angle subtended by the same chord at the circumference of the circle, which is angle QOR. Thus, angle QRS = 1/2 * angle QOR = 1/2 * 90 degrees = 45 degrees. Therefore, the answer is 45 degrees, which is 35^o.