Samacheer Kalvi Class 4 Maths Solutions Term 2 Chapter 3 Patterns Exercise 3.1

I. Draw Symmetrical Lines for the Following Shapes

Question 1.
Answer: A square has four lines of symmetry. These lines divide the square into two identical halves when folded. It means a square is perfectly balanced on all four lines.
In simple words: A square can be folded perfectly in half along four different lines. These lines are its lines of symmetry.

🎯 Exam Tip: Remember that a square has more lines of symmetry (four) than a rectangle (two) because all its sides are equal and all angles are 90 degrees.

Question 2.
Answer: A rectangle has two lines of symmetry. These lines run through the middle, horizontally and vertically, dividing the rectangle into two identical parts. You can fold a rectangle perfectly along these two lines.
In simple words: A rectangle can be folded in half along two lines: one going up-down and one going side-to-side.

🎯 Exam Tip: For rectangles, the lines of symmetry are always straight through the center, parallel to its sides. Diagonal lines do not work for a rectangle unless it is also a square.

Question 3.
Answer: An equilateral triangle, where all three sides are equal, has three lines of symmetry. Each line goes from one corner to the middle of the opposite side. An equilateral triangle is perfectly symmetrical from all its vertices to the midpoints of the opposite sides.
In simple words: An equilateral triangle has three lines where you can fold it to get two matching halves. These lines go from each point to the middle of the side across from it.

🎯 Exam Tip: The number of lines of symmetry in a regular polygon (like an equilateral triangle or square) is equal to the number of its sides.

II. Fill in the Boxes.

Question 1. The pattern shows: small gray square, large black square, small gray square, blue circle, small gray square. The sequence then repeats.
Answer: The pattern is: small gray square, large black square, small gray square, blue circle, small gray square. This sequence repeats. To fill the boxes, you need to continue this order. Therefore, the missing shapes are a large black square, a small gray square, and a blue circle.
In simple words: Look at the order of shapes. Repeat that exact order to fill the empty spots.

🎯 Exam Tip: Pay attention to both the shape, size, and color of each item in the pattern. Any small detail might be part of the repeating rule.

Question 2. The pattern shows: two red triangles, green rectangle, two pink triangles, two dark blue squares. The sequence then repeats.
Answer: The pattern is: two red triangles, a green rectangle, two pink triangles, and two dark blue squares. This whole group of shapes repeats. To complete the pattern, we need to add a green rectangle and then two pink triangles.
In simple words: Find the repeating block of shapes. Then, draw the next shapes that should come in that repeating order.

🎯 Exam Tip: Some patterns involve repeating groups of shapes, not just individual shapes. Identify the full group that repeats.

Question 3. The pattern shows: small gray rectangle, dark blue rectangle, light green rectangle. The sequence then repeats.
Answer: The pattern is a sequence of three different colored rectangles: small gray, dark blue, and light green. This three-rectangle sequence repeats itself. To complete the pattern, we should fill the empty boxes with a dark blue rectangle, a light green rectangle, a small gray rectangle, and another dark blue rectangle.
In simple words: Figure out which three colored rectangles repeat. Then, draw them in the empty boxes following that order.

🎯 Exam Tip: When patterns are simple, sometimes the repeating unit is very short, like just two or three items. Always look for the smallest repeating block.

Question 4. The pattern shows: small green boat, orange triangle pointing right, dark gray boat, black arrow pointing right. The sequence then repeats.
Answer: The pattern is a sequence of four different shapes: a small green boat, an orange triangle pointing right, a dark gray boat, and a black arrow pointing right. This group of four shapes repeats. To complete the pattern, we need to fill the empty boxes with a dark gray boat, a black arrow pointing right, a small green boat, and an orange triangle pointing right.
In simple words: Find the repeating series of four shapes. Then, add those shapes in order to fill the empty spots.

🎯 Exam Tip: When patterns include rotated or mirrored shapes, identify the orientation change as part of the pattern's rule.

III. Complete the Patterns

Question 1. The pattern shows: large diamond with small red square inside, large empty diamond, large diamond with small red square inside, large empty diamond.
Answer: The pattern alternates between a large diamond shape that has a small red square inside it and a large empty diamond shape. This is a two-step repeating pattern. To complete it, the next shapes should be a large diamond with a small red square inside, followed by a large empty diamond.
In simple words: The pattern goes "diamond with red square, then empty diamond." Just continue this back-and-forth pattern.

🎯 Exam Tip: Patterns can involve not just shapes but also what's inside them or changes in their texture or color. Observe all features.

Question 2. The pattern shows: half-green circle (left side filled), black circle with white diamond, half-green circle (left side filled), black circle with white diamond.
Answer: This pattern alternates between two types of circles: one is half-filled green on the left side, and the other is a black circle with a white diamond inside it. This is a simple alternating pattern. To complete it, the next shapes should be a half-green circle (left side filled) followed by a black circle with a white diamond.
In simple words: The pattern goes "half-green circle, then black circle with diamond." Keep switching between these two designs.

🎯 Exam Tip: Pay close attention to colors and any small shapes or designs inside larger ones, as these are often key to understanding the pattern's rule.