NCERT Solutions for Class 4th Maths Chapter 11 . Observe the shapes — In-text Questions
Book page 1705 Updated on2026-09-19
Q1.
Observe the shapes. How many sides does each shape have?The two boxes of shapes printed in the book.
Answer
The first box holds 6 triangles and the second box holds 8 four-sided shapes.
The two boxes of shapes printed in the book.
Box
Shape
Number of sides
First box
Orange triangle (top left)
3
First box
Blue triangle (top right)
3
First box
Purple triangle
3
First box
Orange triangle (middle right)
3
First box
Thin blue triangle
3
First box
Green triangle
3
Second box
Purple kite
4
Second box
Blue rectangle
4
Second box
Light blue square
4
Second box
Orange trapezium
4
Second box
Light blue parallelogram
4
Second box
Orange rhombus (diamond)
4
Second box
Green four-sided shape
4
Second box
Blue arrowhead
4
Why it happens: Count the straight edges of a shape, going once round its border. Every shape in the first box is closed by 3 straight edges, and every shape in the second box by 4.
Tip: The blue arrowhead is a four-sided shape too, even though one of its corners is pushed inwards.
Q2.
How many lines of symmetry does each shape have? You may trace these shapes and check the lines of symmetry by folding the shapes.The two boxes of shapes printed in the book.
Answer
Trace each shape, cut it out and fold it. Count only the folds where the two halves sit exactly on each other.
The two boxes of shapes printed in the book.
Shape
Sides
Lines of symmetry
Orange triangle, top left (square corner, unequal arms)
3
0
Blue triangle, top right (two equal sides)
3
1
Purple triangle (two equal sides)
3
1
Orange triangle, middle right (two equal sides)
3
1
Thin blue triangle (all sides different)
3
0
Green triangle (square corner, two equal arms)
3
1
Purple kite
4
1
Blue rectangle
4
2
Light blue square
4
4
Orange trapezium (slanting sides equal)
4
1
Light blue parallelogram
4
0
Orange rhombus
4
2
Green four-sided shape
4
1
Blue arrowhead
4
1
Every line of symmetry drawn on the shapes, in dashed red.
Why it happens: A fold is a line of symmetry only when each corner lands on another corner and each side lands on a side of the same length. A parallelogram slants, so no fold makes its halves match.
Check it yourself: The green triangle and the green four-sided shape have a slanting line of symmetry, not an upright one. Turn your traced shape and fold corner to corner.