NCERT Solutions for Class 4th Maths Chapter 1 Drawing three- and four-sided shapes on a dot grid — In-text Questions
Book page 15 Updated on2026-09-19
Q1.
Use the dot grid given below to draw several three- and four-sided shapes. Circle the shapes that have one or more right angles.
The dot grid given in the book.
Answer
Join dot to dot to make each shape, then test every corner with your paper
checker.
Three-sided shapes — join any 3 dots that are not in one straight
line.
Four-sided shapes — join any 4 dots so that the lines do not cross.
Put the corner of your folded paper on each corner of the shape.
If it fits exactly at even one corner, draw a ring round that shape.
Shapes that will get a ring
every square and every rectangle — all 4 corners are right
angles;
a triangle drawn with one side along a row and the other side straight down a column
— it has 1 right angle;
a four-sided shape with one side across and the next side straight down — it has
2 right angles.
Why it happens: The dots stand in straight rows and straight
columns. Wherever a side along a row meets a side along a column, that corner is a right
angle.
Q2.
Discuss: What shapes did you make? How many shapes have you made with a) 1 right angle b) 2 right angles c) 3 right angles d) all right angles
The dot grid given in the book.
Answer
Count your own shapes, but check your counts against these facts.
Right angles in the shape
Can it be done?
Example
a) 1 right angle
yes
a triangle with one side across and one side down
b) 2 right angles
yes
a four-sided shape with two square corners on one side
c) 3 right angles
no — it is impossible
as soon as you draw 3 square corners, the fourth corner is square too
d) all right angles
yes
every square and every rectangle
Sample answer: I made 8 shapes. 3 of them had 1 right
angle, 2 had 2 right angles, none had exactly 3 right angles, and 2 were rectangles with
all right angles.
Why it happens: Try it on the grid. Draw three square corners of
a four-sided shape and join the last two dots — the fourth corner always comes out
square as well. So a shape with exactly 3 right angles cannot be made. A triangle
can never have more than 1 right angle either.
Q3.
Here are some 4-sided shapes. In what ways are rectangle and square different from these shapes?
The three four-sided shapes printed in the book.
Answer
The big difference is in the corners.
Rectangle and square
The three shapes in the book
Corners
all 4 are right angles
no right angle at all — two corners are acute and two are obtuse
Sides
opposite sides equal (in a square, all four equal)
the trapezium has only one pair of parallel sides; the rhombus has four equal sides
Look
they stand upright and square
they look pushed over to one side
What is the same: all of them have 4 sides and 4 corners.
Why it happens: A rectangle is the one four-sided shape in which
every side stands square to the next. Push any one side and the square corners are lost
— and then you get shapes like these.