28/21=42/x multiply both sides by x
28/21x=42 divide by 28/21 on both sides ( or multiply both sides by 21/28)
X= 63/2
X= 31 1/2
Answer: Close. Your observation is correct. When you see that the difference between two numbers in the sequence is a perfect square, you are looking at a pyramidal sequence
1² = <u>1 </u> top of pyramid
1 + 2² = <u>5</u> total in top 2 layers
1 + 2² + 3² = <u>14</u> total in top 3 layers
1 + 2² + 3² + 4² = <u>30</u> total in the top 4 layers.
1 + 2² + 3² + 4² + 5² = <u>55</u> total in the top 5 layers.
Layer 6 is 6² more, 91
Layer 7 is 7² more so, 140
I think you got it.
Step-by-step explanation: The numbers are like when you keep adding the layers in a pyramid, and the next number is the total of the previous layers plus the square of the next layer number.
The answer is 2/3 cause the bigger the fraction the smaller it gets so
2/3 > 3/5
