 Welcome to our session. Let us discuss the calling question. The question says, proof that the angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of circle. Using the above, do the calling, proof that the angle formed by a chord in the major segment is acute. Now, we will first prove the first part. We have given a circle with center O, the A O B at the center, point C on remaining part of the circle. We have to prove O B is equal to 2 times angle AC because these are radii O. Let us name this equation as equation number Z equal to 2 times angle O C B. Let us name this as equation number 2, angle A O B down and take care.