Last year there were 15 porcelain dolls in lanny's collection, after trading for a rare doll, she now has 12 dolls. what is the percent decrease of her collection?

step-by-step explanation:

circumference divided by 3.141592654 then timesthe radius twice

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

false

inverse variation is not exponential

the correct answer would be the third option