NCERT Solutions for Class 5th Maths Chapter 3 Paper fan, cardboard house, five-sided shape, gymnasts — Let Us Do
Book page 34–36 Updated on2026-09-19
Q1.
Making a paper fan. Take a rectangular paper, fold every 2 cm as shown in the picture. Paste ice cream sticks as shown below to create a paper fan. Use your paper fan to show different acute angles and obtuse angles.
Making the paper fan, step by step — 1 fold the sheet every 2 cm, 2 press the pleats, 3 close it up, 4 paste one ice cream stick on the top fold and one on the bottom fold, 5 open the sticks out and the fan is ready.
Answer
Here is how to make the fan, step by step.
Take a rectangular sheet of paper, about the size of half a newspaper page.
Mark lines across it every 2 cm with a ruler.
Fold along the first line one way, along the next line the other way, and keep going. This is called pleating — folding to and fro like a hand fan.
Press all the folds flat, then squeeze the pleats together at one end.
Paste one ice cream stick on the front of the folded end and one on the back. Let the glue dry.
Now use the fan to show angles. Hold the bottom stick still on the table. Open the fan by moving only the top stick.
How far you open the fan
What you have shown
just a little
an acute angle
a bit more, but not a square corner
another acute angle
exactly a square corner (a 1/4 turn)
a right angle
wider than a square corner, but not flat
an obtuse angle
fully open and flat
a straight angle (1/2 turn)
Fan opened a little — an acute angle.
Check it yourself: Hold the corner of your notebook inside the opening of the fan. If the fan is narrower than the corner, it is an acute angle. If it is wider, it is an obtuse angle.
Q2.
You might have built houses using the hard covers of notebooks or cardboard pieces. Look at the angles marked in the house. What angles are you able to see in this house? Write your answers as right, acute or obtuse angle. A: ___ B: ___ C: ___ D: ___ E: ___ F: ___ G: ___ H: ___
Answer
Reading the marked corners in the picture:
A: obtuse angle B: right angle C: acute angle D: acute angle E: acute angle F: right angle G: right angle H: acute angle
Mark
Angle
What to look at
A
Obtuse angle
The two roof covers lean apart at the top. The opening is much wider than a square corner.
B
Right angle
The upright pillar stands on the flat book below it — a square corner.
C
Acute angle
The two cards of the little tent lean close together, so the opening at the top is narrow.
D
Acute angle
The slanting card meets the flat base in a narrow, sharp corner.
E
Acute angle
The slanting card meets the upright pillar in a narrow corner.
F
Right angle
The upright side of the block meets the floor in a square corner.
G
Right angle
The upright side of the block meets the flat top in a square corner.
H
Acute angle
The leaning card meets the flat yellow top in a narrow corner.
How to decide, for any corner in the picture:
Put the corner of your notebook on the marked corner of the house.
If the two sides of the house fit the notebook corner exactly, it is a right angle.
If the opening is narrower than the notebook corner, it is an acute angle.
If the opening is wider, it is an obtuse angle.
A right angle — a square corner, like B, F and G.
Tip: Every place where an upright card stands on a flat card gives a right angle. Every place where two cards lean against each other gives an acute angle at the top. A roof that opens out wide gives an obtuse angle.
Q3.
Make a 5-sided shape with 2 right angles, 2 obtuse angles, and 1 acute angle in your notebook.
Answer
Here is a five-sided shape that has exactly those angles — it looks like a little hut.
A hut shape: right angles at A and B, obtuse angles at C and E, and an acute angle at the top, D.
Draw it like this on squared paper.
Draw a base line AB of 6 squares.
At A go straight up 4 squares to E. At B go straight up 4 squares to C. Now A and B are square corners — the 2 right angles.
Find the middle of the top (3 squares from each side) and go up about 5 more squares. Call this point D.
Join E to D, and D to C. Do not join E to C.
You now have five sides: AB, BC, CD, DE and EA.
Angle A = right angle Angle B = right angle Angle C = obtuse angle (wider than a square corner) Angle E = obtuse angle Angle D = acute angle (the sharp point at the top)
Why it happens: The two upright sides give the two square corners at the bottom. Sloping the roof inwards makes the two upper corners open out wider than a square corner, so they become obtuse. The two slopes meet in a sharp point at the top, which is acute.
Check it yourself: Test each of the five corners with the corner of another notebook. You should find exactly 2 that match it, 2 that are wider, and 1 that is narrower.
Q4.
Look at the angle formation between the legs of these gymnasts. Identify whether the angles are acute, obtuse, right or straight.
Five gymnasts, drawn as stick figures. Beside each one is the angle its legs make, with an empty box for your answer.
Answer
Reading the five pictures from top to bottom:
Gymnast
How wide the legs open
Angle
1st (top)
a narrow V — less than a 1/4 turn
acute angle
2nd
exactly a square corner — a 1/4 turn
right angle
3rd
wider than a square corner
obtuse angle
4th
wider still, almost flat
obtuse angle
5th (bottom)
both legs in one straight line — a 1/2 turn
straight angle
The third gymnast: the legs open wider than a square corner — an obtuse angle.
Why it happens: The gymnast’s hips are the corner and her two legs are the two arms of the angle. As she opens her legs wider, the angle grows: acute first, then right at a quarter turn, then obtuse, and at last straight when the legs are in one line (that is called doing the splits).
Tip: The order never changes — acute, right, obtuse, straight. Each one is bigger than the one before.