Answer:

• To solve the equation "n% of 70 is 20":

Let's represent "n%" as "n/100", then we have:

n/100 * 70 = 20

Multiplying both sides by 100/70, we get:

n = 28.57

Therefore, 28.57% of 70 is 20.

• To solve the equation "25% of __ is 65":

Let's represent the missing number as "x", then we have:

25/100 * x = 65

Simplifying the left side, we get:

1/4 * x = 65

Multiplying both sides by 4, we get:

x = 260

Therefore, 25% of 260 is 65.

• To solve the equation "70% of 90 is __":

Let's represent the missing number as "x", then we have:

70/100 * 90 = x

Simplifying the left side, we get:

63 = x

Therefore, 70% of 90 is 63.