Classifying Quadrilaterals — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A square has 4 equal sides but no right angles.
Corrected: A square has 4 equal sides and 4 right angles.
Grade 4 learners remember that a square has 4 equal sides AND 4 right angles, which is why it is a special rectangle.
2. Fix the sentence:
A rectangle has 4 equal sides always.
Corrected: A rectangle has 4 right angles, with opposite sides equal.
Grade 4 students know rectangles need 4 right angles; only opposite sides must be equal, not all four.
3. Fix the sentence:
A trapezoid has two pairs of parallel sides.
Corrected: A trapezoid has exactly one pair of parallel sides.
Grade 4 work on CCSS 4.G.2 defines a trapezoid as a quadrilateral with exactly one pair of parallel sides.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A quadrilateral with 4 equal sides and 4 right angles is a square.
Grade 4 students learn a square has 4 equal sides and 4 right angles, making it a special rectangle and rhombus.
2. A four-sided shape with exactly one pair of parallel sides is a trapezoid.
Grade 4 lessons define a trapezoid as having exactly one pair of parallel sides.
3. A parallelogram with 4 equal sides but no right angles is a rhombus.
Grade 4 work shows a rhombus has 4 equal sides; if it also has 4 right angles, it would be a square.
4. A quadrilateral with two pairs of parallel sides is called a parallelogram.
Grade 4 students recognize parallelograms by their two pairs of parallel sides.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Why is every square also a rectangle?
Sample answer: A square is a rectangle because it has 4 right angles, which is the rule for rectangles. A square also has 4 equal sides, making it a special rectangle.
Grade 4 students see that any shape meeting the rectangle rule (4 right angles) is a rectangle, and squares always do.
2. How can you tell a rhombus from a square?
Sample answer: Both have 4 equal sides. A square also has 4 right angles, but a rhombus does not need right angles. So a tilted rhombus is not a square.
Grade 4 learners use angle measures to separate rhombuses from squares since both share 4 equal sides.