Dial 360 degrees, 360/ 12=30 degrees per hour, and each minimum scale is 6 degrees. At 8:28, the angle between the hour hand and the scale 8 is 30*(28/60)= 14 degrees, and the angle between the scale 7 and the minute hand is 30*2+6*2=72 degrees, so the internal angle formed is 14+72=86 degrees.