Khan academy question pls help.

17

Step-by-step explanation:

Now, I'm not the best at math, so bear with me. But, seeing as the dilations are spread equally across the shape, by looking at the difference between 45 and 35, we see that it is simply a subtraction of 10. So, if you were to subtract 10 from 27 you would get 17 as the undetermined length.

I could be wrong, I'm not the best at math by any means, but I'm pretty sure that's the correct answer.

is there a picture

step-by-step explanation:

, 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