Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions Chapter-16. We provide step by step Solutions of Exercise / lesson-16 Symmetry Reflection and Rotation Class-8th ML Aggarwal ICSE Mathematics.
Our Solutions contain all type Questions with Exe-16 Objective Type Questions (including Mental Maths Multiple Choice Questions ) and Check Your Progress to develop skill and confidence. Visit official Website CISCE for detail information about ICSE Board Class-8 Mathematics.
Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions Chapter-16
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Objective Type Questions,
Multiple Choice Questions ,(MCQ)
Exercise-16, Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions
Question 1.
Draw the line or lines of symmetry, if any, of the following shapes and count their number :
Answer
Question 2.
For each of the given shape in question 1, find the order of the rotational symmetry (if any).
Answer
(i) None
(ii) None
(iii) Two
(iv) Four
(v) Three
(vi) Four
Question 3.
Construct a rectangle ABCD such that AB = 4.5 cm and BC = 3 cm. Draw its line (or lines) of symmetry.
Answer
(i) Draw a line AB = 4.5 cm.
(ii) Draw a line BQ from point B making an angle of 90°.
(iii) Taking B as centre and radius = 3 cm,
mark an arc on BQ, name it as C.
(iv) As we know, opposite sides of rectangle are equal.
Therefore from point C. As a centre and radius = 4.5 cm,
draw an arc and with A as centre and 3 cm as radius,
make another as C, cutting the previous arc at point D.
(v) Join DC and DA.
(vi) ABCD is a required rectangle.
Lines of symmetry:
It has 2 lines of symmetry,
the lines joining the midpoints of opposite sides.
Question 4.
Construct a rhombus ABCD with AB = 5.3 cm and ∠A = 60°. Draw its line (or lines) of symmetry.
Answer
(i) Draw line segment AB = 5.3 cm.
(ii) Construct ∠BAX = 60°.
(iii) With A as centre, radius = 5.3 cm draw an arc on AX.
(iv) Mark the point of intersection = D.
(v) With D as the centre and radius = 5.3 cm, draw an arc.
(vi) With B as centre and same radius,
draw another arc, such that it intersects the previous at C.
(vii) Join CD and CB.
ABCD is a required rhombus.
Lines of symmetry in rhombus = 2,
the diagonals of the rhombus.
Objective Type Questions
Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions Chapter-16
Mental Maths
Question 1.
Fill in the blanks:
(i) A figure has ………….. symmetry if it is its own image under a reflection.
(ii) A kite has ………….. line(s) of symmetry.
(iii) A parallelogram has ………….. line(s) of symmetry.
(iv) The centre of rotation of an equilateral triangle is the point of intersection of its …………..
(v) The centre of rotation of a rhombus is the point …………..
(vi) A regular polygon of n-sides has ………….. number of lines of symmetry.
(vii) Angle of rotational symmetry in an equilateral triangle is …………..
(viii) Angle of rotational symmetry in a regular pentagon is …………..
(ix) If after a rotation of 45° about a fixed point the figure looks exactly the same, then the order of rotational symmetry is …………..
Answer
(i) A figure has line symmetry if it is its own image under a reflection.
(ii) A kite has one line(s) of symmetry.
(iii) A parallelogram has none line(s) of symmetry.
(iv) The centre of rotation of an equilateral triangle is the
point of intersection of its angle bisectors/altitudes/median.
(v) The centre of rotation of a rhombus is the
point of intersection of its diagonals.
(vi) A regular polygon of n-sides has n number of lines of symmetry.
(vii) Angle of rotational symmetry in an equilateral triangle is 120°.
(viii) Angle of rotational symmetry in a regular pentagon is 72°.
(ix) If after a rotation of 45° about a fixed point the figure looks
exactly the same, then the order of rotational symmetry is 8.
Question 2.
State whether the following statements are true (T) or false (F):
(i) A parallelogram has diagonals as its lines of symmetry.
(ii) A regular triangle has three lines of symmetry, one point of symmetry and has rotational symmetry of order 3.
(iiii) A, regular quadrilateral has four lines of symmetry, one point of symmetry and has . rotational symmetry of order 4.
(iv) A parallelogram has no rotational symmetry.
(v) A regular pentagon has one point of symmetry.
(vi) The letter Z has one line of symmetry.
Answer
(i) A parallelogram has diagonals as its lines of symmetry. False
Correct:
A parallelogram has no line of symmetry.
(ii) A regular triangle has three lines of symmetry,
one point of symmetry and has rotational symmetry of order 3. False
Correct:
A rectangle has 2 lines of symmetry,
one point of symmetry and rotational symmetry of order 2.
(iii) A regular quadrilateral has four lines of symmetry,
one point of symmetry and has rotational symmetry of order 4. True
(iv) A parallelogram has no rotational symmetry. False
Correct:
A parallelogram has rotational symmetry of order 2.
(v) A regular pentagon has one point of symmetry. False
Correct:
A regular pentagon has no point of symmetry.
(vi) The letter Z has one line of symmetry. False
Correct:
The letter Z has no line of symmetry.
Multiple Choice Questions
MCQs of Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions Chapter-16
Choose the correct answer from the given four options (3 to 6):
Question 3.
The number of lines of symmetry which a quadrilateral cannot have
(a) 1
(b) 2
(c) 3
(d) 4
Answer
Number of lines of symmetry in
a quadrilateral cannot have three. (c)
Question 4.
A possible angle of rotation of a figure having rotational symmetry of order greater than or equal to 2 is
(a) 36°
(b) 144°
(c) 150°
(d) 360°
Answer
Two possible angles of rotation of a figure having rotational
symmetry of order greater than or equal to 2 is 36°. (a)
Question 5.
The figure which does not have both line and rotational symmetry is
Answer
The figure which does not have both lines
and rotational symmetry is a figure given in (c).
Question 6.
The letter which has both line and rotational symmetry is
Answer
The letter which has both lines and rotational symmetry is 
.
Check Your Progress
Chapter-16 Symmetry Reflection and Rotation Class-8 ML Aggarwal Mathematics Solutions
Question 1.
Draw the line (or lines) of symmetry, if any, of the following shapes and count their number :
Answer
Question 2.
For each of the given shape in question 1, find the order of the rotational symmetry (if any).
Answer
(i) Two
(ii) Two
(iii) Three
Question 3.
Write the letters of the word ‘NEW ALGEBRA’ which have no line of symmetry.
Answer
In the word ‘NEW ALGEBRA’
These letters are N, L, G and R.
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