What decrease the probability of something happening?

When you add more to your sample space.

Imagine you have a 6-sided dice and you change it to a 10-sided dice. Your possibilities of getting any number (excluding 7, 8, 9, 10), just went from 16.67% to 10%.

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6