Lines and Symmetry — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Which shape has exactly 4 lines of symmetry?
A) Rectangle
B) Rhombus
C) Square
D) Trapezoid
A square has 4 lines of symmetry: vertical, horizontal, and both diagonals. A rectangle has 2; a rhombus has 2; a trapezoid has at most 1.
2. What angle do perpendicular lines form?
A) 45°
B) 60°
C) 90°
D) 180°
Perpendicular lines meet at right angles, which measure exactly 90°.
3. How many lines of symmetry does a parallelogram that is not a rectangle or rhombus have?
A) 0
B) 1
C) 2
D) 4
A general parallelogram has no lines of symmetry — no fold produces two matching halves.
4. A regular polygon has 10 sides. How many lines of symmetry does it have?
A) 5
B) 8
C) 10
D) 20
For any regular polygon, the number of lines of symmetry equals the number of sides. 10 sides → 10 lines of symmetry.
Part B: Fill in the Blank
Write the correct answer on each line.
1. A shape and its reflection across a line of symmetry are identical.
When a shape is reflected across its line of symmetry, the reflected image is congruent to — identical to — the original.
2. A regular heptagon has 7 lines of symmetry.
A regular heptagon has 7 equal sides → 7 lines of symmetry.
3. Two parallel lines cut by a perpendicular line form 4 right angles.
A line perpendicular to two parallel lines creates 4 right angles in total (2 at each intersection).
4. The number of lines of symmetry in a regular polygon equals the number of its sides.
This is the rule for all regular polygons: lines of symmetry = number of sides (= number of vertices).
5. A kite has 1 line(s) of symmetry.
A kite has exactly one line of symmetry — the diagonal connecting the two vertices where the unequal sides meet.