krit.club logo

Play with Patterns - Shape Patterns

Grade 4CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Understanding Patterns: A pattern is a sequence where shapes, colors, or designs repeat in a specific order. For example, a sequence showing a red circle followed by a blue square, then repeating that same pair, forms a basic repeating pattern.

Repeating Patterns: These are patterns where the core unit stays exactly the same as it repeats. In a visual sequence like ,,,,,\bigtriangleup, \square, \bigcirc, \bigtriangleup, \square, \bigcirc, the core unit is ,,\bigtriangleup, \square, \bigcirc. To find the next shape, you identify where the sequence starts over.

Growing Patterns: In these patterns, the elements change according to a rule, usually getting larger or adding more parts. For example, if the first step is a single dot \cdot, the second is a 2×22 \times 2 square of dots, and the third is a 3×33 \times 3 square of dots, the pattern is growing by increasing the side length of the square by 11 each time.

Rotational Patterns (Turns): Shapes often change their orientation using turns. A 14\frac{1}{4} turn rotates a shape by 9090^{\circ} clockwise (like a clock hand moving from 12 to 3). A 12\frac{1}{2} turn rotates it by 180180^{\circ}, making it appear upside down compared to its original position.

Mirror Symmetry in Patterns: Some patterns are created by reflecting a shape across a line of symmetry. If you see a shape like the letter 'E' and the next shape is its mirror image '彐', they form a symmetrical pattern. The line of symmetry acts like a mirror placed vertically or horizontally.

Tiling and Tessellations: This is a type of shape pattern that covers a flat surface completely without any gaps or overlaps. Think of a bathroom floor with hexagonal tiles or a brick wall; the shapes fit together perfectly to create a continuous pattern.

Identifying the Pattern Rule: To solve any pattern problem, you must find the 'rule'. This is done by comparing the first term to the second term and checking if that same change applies to the third term. The rule could be 'Rotate 9090^{\circ} clockwise' or 'Add one more side to the polygon'.

📐Formulae

Rule=The logical link between term n and term n+1\text{Rule} = \text{The logical link between term } n \text{ and term } n+1

14 Turn=90 rotation\frac{1}{4} \text{ Turn} = 90^{\circ} \text{ rotation}

12 Turn=180 rotation\frac{1}{2} \text{ Turn} = 180^{\circ} \text{ rotation}

34 Turn=270 rotation\frac{3}{4} \text{ Turn} = 270^{\circ} \text{ rotation}

1 Full Turn=360 rotation1 \text{ Full Turn} = 360^{\circ} \text{ rotation}

Growing Square Pattern Area=n×n (where n is the step number)\text{Growing Square Pattern Area} = n \times n \text{ (where } n \text{ is the step number)}

💡Examples

Problem 1:

Observe the sequence of arrows: \uparrow (pointing up), \rightarrow (pointing right), \downarrow (pointing down). What will be the next two arrows in this pattern?

Solution:

  1. Identify the change: The arrow is rotating clockwise. \ 2. Measure the turn: Each step is a 14\frac{1}{4} turn (9090^{\circ}). \ 3. Apply the rule: After pointing down (\downarrow), a 14\frac{1}{4} turn clockwise points the arrow to the left (\leftarrow). \ 4. Next step: Another 14\frac{1}{4} turn from left brings the arrow back to its starting position, pointing up (\uparrow). \ The next two shapes are \leftarrow and \uparrow.

Explanation:

This is a rotational pattern where the shape turns by a fixed angle in each step.

Problem 2:

A growing pattern of blocks is as follows: \ Step 1: 11 block \ Step 2: 33 blocks (forming a small 'L' shape) \ Step 3: 55 blocks (forming a larger 'L' shape) \ How many blocks will be required for Step 6?

Solution:

  1. List the number of blocks: 1,3,5,1, 3, 5, \dots \ 2. Find the difference: 31=23 - 1 = 2 and 53=25 - 3 = 2. The rule is to add 22 blocks at each step. \ 3. Continue the sequence: \ Step 4: 5+2=75 + 2 = 7 \ Step 5: 7+2=97 + 2 = 9 \ Step 6: 9+2=119 + 2 = 11 \ Step 6 will have 1111 blocks.

Explanation:

This is a growing pattern where the number of blocks increases by a constant addition of 22 for every new step.