Question

class: vii
date : 26-08-25
l. - 12, 13
assignment- 3 (semester - i)
sub: math
date of submission : 01-09-25
lesson - 12 symmetry
♦ fill in the blanks.

1. in an isosceles right triangle, the number of lines of symmetry is.
2. the number of lines of symmetry of a semi - circle is.
3. a full turn means a rotation of degrees.
4. is a figure that has neither a line of symmetry nor a rotational symmetry.
5. the mirror image of d is.
6. each regular polygon has as many lines of symmetry as it has.

♦ state whether the given statements are true or false.

1. the order of symmetry for an equilateral triangle is 3.
2. a regular hexagon has five lines of symmetry.
3. the mirror image of r is r.
4. at 6 oclock the hour and minute hand of clock will make a quarter turn.
5. z has no line of symmetry.
6. the angle of turning during rotation is called the angle of rotation.

♦ choose the correct option from the given alternatives.

1. the order of rotation of z is.

a) 2 b) 3 c) 1

1. which of the following alphabet has horizontal line of symmetry?

a) b b) e c) all of these

1. the other name for line of symmetry of semi - circle is.

a) diameter b) radius c) none of these

1. has lines of symmetry.

a) 6 b) 5 c) 0
♦ do as directed.

1. show that each of the letters h, i, n, s, x and z has a rotational symmetry of order 2?
2. write four english alphabets which have vertical line of symmetry.
3. show mirror image of the following words.

(a) maths (b) ok (c) no (d) it
lesson-13 visualing solid shapes
♦ fill in the blanks.

1. a pyramid has faces in the shape of.
2. a circle is a shape.
3. a cuboid has vertices.
4. an sketch does not have proportional lengths.

♦ state whether the given statements are true or false.

1. a cylinder has no vertex.
2. all faces, except the base of a square pyramid are triangular.
3. rectangle is a 3 - d shape.
4. a cube has 5 faces.

Explanation:

Fill in the blanks (Lesson - 12 Symmetry)

1. In an isosceles right triangle, the number of lines of symmetry is 1.
2. The number of lines of symmetry of a semi - circle is 1.
3. A full turn means a rotation of 360 degrees.
4. A scalene triangle is a figure that has neither a line of symmetry nor a rotational symmetry. (There are other possible answers like an irregular quadrilateral etc.)
5. The mirror image of D is D (if the mirror is placed vertically).
6. Each regular polygon has as many lines of symmetry as it has sides.

True or False (Lesson - 12 Symmetry)

1. The order of symmetry for an equilateral triangle is 3. True

An equilateral triangle can be rotated 3 times to coincide with itself in a 360 - degree turn.

1. A regular hexagon has five lines of symmetry. False

A regular hexagon has 6 lines of symmetry.

1. The mirror image of R is R. False

The mirror image of R is not the same as R.

1. At 6 o'clock the hour and minute hand of clock will make a quarter turn. False

Answer:

A cube has 6 faces.