Attributes of Shapes — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A rhombus always has 4 right angles.
Corrected: A rhombus has 4 equal sides but does not always have right angles.
A rhombus is defined only by having 4 equal sides — its angles can lean and tilt, so it usually looks like a slanted diamond rather than a perfect square.
2. Fix the sentence:
A decagon has 8 sides and 8 angles.
Corrected: A decagon has 10 sides and 10 angles.
The prefix 'deca-' means ten (think of a decade being 10 years), so a decagon must have 10 sides and 10 matching angles.
3. Fix the sentence:
An open figure with straight sides is a polygon.
Corrected: A closed figure with straight sides is a polygon.
A polygon must be closed so the sides form a complete boundary with no gaps — an open figure with a missing side cannot be a polygon.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A polygon with 10 sides is called a decagon.
A decagon takes its name from 'deca,' the Greek root for ten — the same root used in decade, decimal, and decathlon.
2. A square is a special rhombus because all 4 sides are equal.
Any quadrilateral with 4 equal sides is a rhombus, and a square fits that rule perfectly — it is just a rhombus that also happens to have 4 right angles.
3. Lines that run side by side and never meet are called parallel lines.
Parallel lines stay the same distance apart no matter how far they stretch, like the two long rails of a railroad track.
4. A quadrilateral always has 4 angles.
The prefix 'quad-' means four, so every quadrilateral has 4 sides — and each pair of sides meets to form one of its 4 angles.
Part C: True or False?
Read each statement. Circle True or False.
1. Every rhombus is a parallelogram.
True False
True — a rhombus has both pairs of opposite sides parallel, which is the exact rule that makes any quadrilateral a parallelogram.
2. A hexagon has 5 vertices.
True False
False — 'hex' means six, so a hexagon has 6 sides and 6 vertices; a shape with 5 vertices would be a pentagon.
3. All polygons have straight sides.
True False
True — straight sides are part of the definition of a polygon, which is why circles and ovals are not polygons.