Attributes of Shapes — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Two lines that meet at a 90-degree angle are called perpendicular lines.
A 90-degree angle is a right angle, and 'perpendicular' is the special name we use whenever two lines cross to make that exact square corner.
2. A pentagon has 5 vertices.
'Penta' means five, so a pentagon has 5 sides — and since each side ends at a corner, it must also have 5 vertices.
3. A rectangle has perpendicular sides that form 4 right angles.
Every corner of a rectangle is where two perpendicular sides meet, and a rectangle has 4 corners, so it forms 4 right angles.
4. A shape with exactly 3 vertices and 3 sides is a triangle.
The word 'triangle' starts with 'tri,' which means three — it is the only polygon that has exactly 3 sides and 3 corners.
5. A decagon has 10 sides and 10 angles.
'Deca' means ten, so a decagon has 10 sides — and because every polygon has the same number of angles as sides, it has 10 angles too.
6. Opposite sides of a rectangle are both equal and parallel.
In a rectangle, the top runs side by side with the bottom and never bends toward it, so opposite sides are parallel as well as the same length.
7. A quadrilateral with no parallel sides and no equal sides is called an irregular quadrilateral.
'Irregular' means the sides and angles do not follow a matching pattern — when no sides are equal and none are parallel, the shape has no regularity at all.
8. A rhombus has 4 equal sides.
Having 4 sides of the exact same length is the rule that makes a quadrilateral a rhombus — that is what gives it its diamond shape.
9. A polygon must be a closed shape made of straight lines.
A polygon must be closed so the sides connect end-to-end with no gaps; if even one side is missing, the figure is open and is not a polygon.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Parallelogram
→ 2 pairs of parallel sides, opposite sides equal
No parallel sides, no equal sides
Trapezoid
→ Exactly 1 pair of parallel sides
4 equal sides, 4 right angles
Square
→ 4 equal sides, 4 right angles
2 pairs of parallel sides, opposite sides equal
Irregular quadrilateral
→ No parallel sides, no equal sides
Exactly 1 pair of parallel sides
Correct matches: Parallelogram → 2 pairs of parallel sides, opposite sides equal; Trapezoid → Exactly 1 pair of parallel sides; Square → 4 equal sides, 4 right angles; Irregular quadrilateral → No parallel sides, no equal sides.