Regular Polygons: Definitions & Vocabulary

10th Grade

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Cierra is an educational consultant and curriculum developer who has worked with students in K-12 for a variety of subjects including English and Math as well as test prep. She specializes in one-on-one support for students especially those with learning differences. She holds an MBA from the University of Massachusetts Amherst and a certificate in educational consulting from UC Irvine.

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By Thames

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Quizzes Created: 8157 | Total Attempts: 9,569,759

| Attempts: 168 | Questions: 20 | Updated: Jan 16, 2026

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1) Which of the following is not a polygon?

Triangle

Circle

Pentagon

Octagon

A polygon is a closed figure with straight sides. A triangle, pentagon, and octagon have straight sides, while a circle does not, making it the only option that is not a polygon.

Explanation

A polygon is a closed figure with straight sides. A triangle, pentagon, and octagon have straight sides, while a circle does not, making it the only option that is not a polygon.

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About This Quiz

Regular Polygons: Definitions & Vocabulary - Quiz

Are you ready to learn the language of polygons? In this quiz, you’ll explore what makes a polygon regular, meaning all its sides and angles are equal. You’ll practice identifying examples like squares, triangles, and hexagons, and learn new words like equilateral and equiangular. By the end, you’ll be able... see moreto spot regular polygons and tell them apart from irregular ones with ease!
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2) What first name or nickname would you like us to use?

You may optionally provide this to label your report, leaderboard, or certificate.

2) A square is considered a regular polygon because

It has opposite sides parallel

All sides and all angles are equal

It has right angles only

Its diagonals are equal

A square is classified as a regular polygon because it has all sides of equal length and all interior angles equal to 90 degrees, satisfying the definition of a regular polygon.

Explanation

A square is classified as a regular polygon because it has all sides of equal length and all interior angles equal to 90 degrees, satisfying the definition of a regular polygon.

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3) The prefix "deca" in decagon means

The prefix 'deca-' comes from Greek, meaning ten. In geometry, a decagon is a polygon with ten sides.

Explanation

The prefix 'deca-' comes from Greek, meaning ten. In geometry, a decagon is a polygon with ten sides.

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4) A regular hexagon has how many equal sides?

A regular hexagon is defined as a six-sided polygon where all sides are of equal length. Therefore, it has 6 equal sides.

Explanation

A regular hexagon is defined as a six-sided polygon where all sides are of equal length. Therefore, it has 6 equal sides.

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5) Which polygon can be regular?

Triangle

Pentagon

Octagon

All of the above

A polygon is considered regular if all its sides and angles are equal. Triangles, pentagons, and octagons can all be regular shapes if they meet these criteria.

Explanation

A polygon is considered regular if all its sides and angles are equal. Triangles, pentagons, and octagons can all be regular shapes if they meet these criteria.

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6) A regular pentagon has how many sides?

A regular pentagon is defined as a five-sided polygon, where all sides and angles are equal. Therefore, the correct answer is 5.

Explanation

A regular pentagon is defined as a five-sided polygon, where all sides and angles are equal. Therefore, the correct answer is 5.

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7) Which of the following is a regular polygon?

Rectangle

Square

Isosceles trapezoid

Scalene triangle

A regular polygon is a polygon with all sides and angles equal. A square fits this definition, while the other options do not.

Explanation

A regular polygon is a polygon with all sides and angles equal. A square fits this definition, while the other options do not.

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8) A polygon with 8 equal sides and 8 equal angles is called

Regular heptagon

Regular octagon

Regular decagon

Irregular octagon

A polygon with 8 equal sides and angles is known as a regular octagon, as 'octo' refers to eight.

Explanation

A polygon with 8 equal sides and angles is known as a regular octagon, as 'octo' refers to eight.

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9) Which of the following is an example of a 3-sided regular polygon?

Scalene triangle

Equilateral triangle

Isosceles triangle

Right triangle

An equilateral triangle is a regular polygon because all three of its sides and angles are equal, making it a specific type of triangle with three equal sides.

Explanation

An equilateral triangle is a regular polygon because all three of its sides and angles are equal, making it a specific type of triangle with three equal sides.

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10) Which of the following is a regular quadrilateral?

Square

Rectangle

Rhombus

Parallelogram

A regular quadrilateral is one where all sides and angles are equal. A square meets this criterion, while a rectangle, rhombus, and parallelogram do not necessarily have all equal angles or sides.

Explanation

A regular quadrilateral is one where all sides and angles are equal. A square meets this criterion, while a rectangle, rhombus, and parallelogram do not necessarily have all equal angles or sides.

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11) A regular polygon is defined as having:

All sides equal

All angles equal

All sides and all angles equal

All right angles

A regular polygon is characterized by having both equal sides and equal angles, which distinguishes it from other polygons that may have sides of different lengths or angles of different measures.

Explanation

A regular polygon is characterized by having both equal sides and equal angles, which distinguishes it from other polygons that may have sides of different lengths or angles of different measures.

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12) The word 'equiangular' means?

All sides are equal

All angles are equal

Two sides are equal

Two angles are equal

The term 'equiangular' refers to a shape where all angles are equal in measure. This is commonly seen in geometric figures such as regular polygons.

Explanation

The term 'equiangular' refers to a shape where all angles are equal in measure. This is commonly seen in geometric figures such as regular polygons.

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13) A polygon with all angles equal but sides not equal is called

Regular

Equilateral

Equiangular but irregular

Impossible

A polygon that has all equal angles but unequal sides is known as equiangular but irregular. This means that while the internal angles are the same, the lengths of the sides can vary.

Explanation

A polygon that has all equal angles but unequal sides is known as equiangular but irregular. This means that while the internal angles are the same, the lengths of the sides can vary.

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14) Which feature distinguishes regular polygons from irregular polygons?

Only regular polygons can be convex

Irregular polygons must have curved sides

Irregular polygons always have diagonals perpendicular

Regular polygons have all sides and angles equal

This is the key difference — irregular polygons have unequal sides or angles (or both).

Explanation

This is the key difference — irregular polygons have unequal sides or angles (or both).

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15) The word "equilateral" means

All angles are equal

All sides are equal

All angles are 90°

None of the angles are equal

An equilateral triangle has all three sides of equal length, which also means all angles are equal, each measuring 60 degrees.

Explanation

An equilateral triangle has all three sides of equal length, which also means all angles are equal, each measuring 60 degrees.

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16) Which polygon is both equilateral and equiangular with 5 sides?

Pentagon

Regular pentagon

Regular hexagon

Irregular pentagon

A regular pentagon is both equilateral (all sides are the same length) and equiangular (all angles are equal), making it the only polygon with 5 sides that has these properties.

Explanation

A regular pentagon is both equilateral (all sides are the same length) and equiangular (all angles are equal), making it the only polygon with 5 sides that has these properties.

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17) A polygon with all sides equal but angles not equal is called

Equilateral but irregular

Equiangular

Regular

Impossible

Equal sides but unequal angles mean it’s not regular—a rhombus is a good example.

Explanation

Equal sides but unequal angles mean it’s not regular—a rhombus is a good example.

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18) Which of the following is a convex regular polygon?

Square

Equilateral triangle

Regular hexagon

All of the above

A convex regular polygon is defined as a polygon with all sides and angles equal, and it does not have any interior angles greater than 180 degrees. All the options listed (square, equilateral triangle, and regular hexagon) meet these criteria, thus the correct answer is 'All of the above'.

Explanation

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19) The diagonals of a regular polygon are

Always equal

Always perpendicular

Always unequal

Sometimes equal

In a regular polygon, the lengths of the diagonals can vary depending on the vertices chosen, meaning that some diagonals can be equal while others may not be. This is why the correct answer is 'Sometimes equal'.

Explanation

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20) Which of the following is a convex regular polygon?

It has curved sides

It has at least one angle greater than 180°

It always has 4 sides

It must be equilateral

A convex regular polygon is defined as having all angles less than 180° and all sides equal. Therefore, it cannot have any angle greater than 180°.

Explanation

A convex regular polygon is defined as having all angles less than 180° and all sides equal. Therefore, it cannot have any angle greater than 180°.

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