What Is the 10-20-30 Rule

What is the 10-20-30 rule?

A) 30% of the audience will grasp 20% of your statistics if you speak longer than 10 minutes.
B) Use no more than 10 slides, no more than 20 minutes, and never use text on a slide smaller than 30 points.
C) Font size = oldest age/20
D) The ratio of proofs should be 10 ethos to 20 pathos to 30 logos
E) A revision of the visual principle of one-thirds.