You could draw a circle for the first two and split it into 4. Shade in 1 section and label 25%. Then say that 25% is 1/4 of the circle. For 50%, draw another circle, and split it into 4 again. This time, shade in 2 sections. Label as 50%. Then say that 50% is 1/2 of a circle. Draw another circle and split it into 6 sections. Label as 150%. Then label that each section is 25% and a circle split in 6 at each section at 25% would be 150% for the whole circle.
