RS Aggarwal Class 7 Math Eighteenth Chapter Reflection and Rotational Symmetry Exercise 18A Solution

EXERCISE 18A

(1) A scalene triangle has

Ans: (a) no line of symmetry.

(2) A rectangle is symmetrical about

Ans: (c) a line joining the midpoints of its opposite sides.

(3) A square has

Ans: (d) four lines of symmetry.

(4) A rhombus is symmetrical about

Ans: (b) each of its diagonals.

(5) A circle has

Ans: (d) an unlimited number of lines of symmetry.

(6) In ∆ABC, AB = AC and AD ⊥ BC, BE ⊥ AC and CF ⊥ AB. Then, ∆ABC is symmetrical about

Ans: (a) AD

(7) ABCD is a kite in which AB = AD and BC = DC. The kite is symmetrical about

Ans: (a) the diagonal AC.

(8) The letter O of the English alphabet has

Ans: (c) two lines of symmetry.

(9) The letter Z of the English alphabet has

Ans: (a) no line of symmetry.

(10) Draw the line (or lines) of symmetry of each of the following figures.

(11) Which of the following statements are true and which of them are false?

(i) A parallelogram has no line of symmetry. = True

(ii) An angle with equal arms has its bisector as the line of symmetry. = True

(iii) An equilateral triangle has three lines of symmetry. = True

(iv) A rhombus has four lines of symmetry. = False

(v) A square has four lines of symmetry. = True

(vi) A rectangle has two lines of symmetry. = True

(vii) Each one of the letters H, I, O, X of the English alphabet has two lines of symmetry. = True

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