Geometric Square Sequence: Finding the 46-Square Structure Pattern

Question

The following is a series of structures formed by squares with side lengths of 1 cm.

Is it possible for a structure to have 46 squares? If so, which element of the series is it?

Video Solution

Solution Steps

00:00 Will there be a term with 46 squares? If so, at what position?
00:03 Let's count the squares in each term
00:25 We can see that the number of squares equals the term's position in the sequence
00:34 Therefore, we can conclude this is the sequence formula
00:40 We want to find if there is a term with 46 squares
00:45 Let's substitute into the formula and solve for N
00:50 Let's isolate N
00:53 The solution is not a whole number, therefore no such term exists
00:57 And this is the solution to the question

Step-by-Step Solution

To determine whether a structure can have exactly 46 squares and identify which element of the series it corresponds to, we must first recognize the growth pattern of the series of squares in the diagram.

From examining patterns in geometric series, commonly encountered shapes include arrangements forming triangles or squares. Typically, triangular numbers are related to sums of consecutive integers:

The nn-th triangular number is given by:

Tn=n(n+1)2 T_n = \frac{n(n+1)}{2}

Let's calculate the first few triangular numbers to understand the sequence:

  • T1=1×(1+1)2=1 T_1 = \frac{1 \times (1+1)}{2} = 1
  • T2=2×(2+1)2=3 T_2 = \frac{2 \times (2+1)}{2} = 3
  • T3=3×(3+1)2=6 T_3 = \frac{3 \times (3+1)}{2} = 6
  • T4=4×(4+1)2=10 T_4 = \frac{4 \times (4+1)}{2} = 10
  • T5=5×(5+1)2=15 T_5 = \frac{5 \times (5+1)}{2} = 15
  • T6=6×(6+1)2=21 T_6 = \frac{6 \times (6+1)}{2} = 21
  • T7=7×(7+1)2=28 T_7 = \frac{7 \times (7+1)}{2} = 28
  • T8=8×(8+1)2=36 T_8 = \frac{8 \times (8+1)}{2} = 36
  • T9=9×(9+1)2=45 T_9 = \frac{9 \times (9+1)}{2} = 45
  • T10=10×(10+1)2=55 T_{10} = \frac{10 \times (10+1)}{2} = 55

Now, check if 46 is among these numbers, as this would indicate a structure with exactly that many squares.

Checking the sequence above, 4646 does not appear. 4545 is the highest number before 4646, and 5555 is the nearest higher one.

Since 4646 is not found in the series of triangular numbers, it is not possible for a structure in this series to have exactly 46 squares.

Therefore, the final answer is No.

Answer

No