Okay, i'm going to re explain this. (Sorry) Okaay..... The question is, how many blocks to you need to make a 20 step stair case. *BACKGROUND INFORMATION* To make a 3 step staircase you only need 6 blocks.
I already know how many blocks i need for a 20 step staircase. What i need help with is creating an expression/rule for it. Does that make sence? If it doesn't...i'm sorry.
Thanks!! :)
How about a proportion?
3 / 6 = 20 / x
look back here
http://www.jiskha.com/display.cgi?id=1211844860
No problem! I understand your question now. To create a rule or expression for the number of blocks needed to make a 20-step staircase, you first need to identify the pattern or relationship between the number of steps and the number of blocks needed.
Based on the given background information, we know that for a 3-step staircase, 6 blocks are needed. To find the number of blocks needed for a 20-step staircase, we can observe that the number of blocks increases by 2 for every additional step.
Let's break it down:
- For a 3-step staircase, we need 6 blocks.
- For a 4-step staircase, we need 8 blocks (increased by 2 blocks).
- For a 5-step staircase, we need 10 blocks (increased by 2 blocks again).
- For a 6-step staircase, we need 12 blocks (increased by 2 blocks again).
We can see that for every additional step, we add 2 blocks. So, to find the number of blocks needed for a 20-step staircase, we can use the following expression:
Number of blocks = (Number of steps - 3) x 2 + 6.
Plugging in 20 for the number of steps, we can calculate the number of blocks needed:
Number of blocks = (20 - 3) x 2 + 6 = 17 x 2 + 6 = 34 + 6 = 40 blocks.
So, you would need 40 blocks to make a 20-step staircase.