13. In the diagram shown, a metal support brace is added to stabilize a metal triangle. The brace is parallel to the 18-foot base of the triangle and divides the left side into a 4-foot and a 6-foot
section. What is the length of the metal support brace?
4 ft
6 ft
18 ft

, 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

i dont get the question

step-by-step explanation: