1. The problem asks for the size of angle ABC, where points A, B, and C lie on a semicircular protractor. 2. Point B is at 0 degrees on the flat edge, point A is at 180 degrees, and point C is near 30 degrees. 3. The angle ABC is the angle formed at point B between points A and C. 4. Since B is at 0 degrees, A at 180 degrees, and C at 30 degrees, the angle ABC is the difference between the positions of A and C relative to B. 5. The angle between A and C at B is $180^\circ - 30^\circ = 150^\circ$ if measured clockwise, but since the angle is shaded between A and C near 30 degrees, the smaller angle is $30^\circ$. 6. Therefore, the size of angle ABC to the nearest degree is $30^\circ$. Final answer: $30^\circ$