SOLUTION: Word problem:You are creating a window display at a toy store using wooden blocks. The display involves stacking blocks in triangular forms. You begin the display with 1 block, whi

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Question 96539This question is from textbook algebra 2
: Word problem:You are creating a window display at a toy store using wooden blocks. The display involves stacking blocks in triangular forms. You begin the display with 1 block, which is your first "triangle," and then stack 3 blocks, two on the bottom and one on the top, to get the next triangle. YOu create the next three triangles by stacking 6 blocks, then 10 blocks, and then 15 blocks. HOw many blocks will you need for the ninth triangle.
I need to make an equation to figure out how many blocks are needed to make the ninth triganle. I know the answer is 45 blocks, but I don't understand how to create the equation with the appropriate variables.
I made an input, output chart to try and figure out the correct equation, but i just couldn't figure it out.

This is due by tommorrow. I will continue to work on it until, i get a response from you.
Thanks!
This question is from textbook algebra 2

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Word problem:You are creating a window display at a toy store using wooden blocks. The display involves stacking blocks in triangular forms. You begin the display with 1 block, which is your first "triangle," and then stack 3 blocks, two on the bottom and one on the top, to get the next triangle. YOu create the next three triangles by stacking 6 blocks, then 10 blocks, and then 15 blocks. HOw many blocks will you need for the ninth triangle.
I need to make an equation to figure out how many blocks are needed to make the ninth triganle. I know the answer is 45 blocks, but I don't understand how to create the equation with the appropriate variables.
I made an input, output chart to try and figure out the correct equation, but i just couldn't figure it out.
=================
f(x)= (x^2+x)/2
=================
Cheers,
Stan H.


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