Comprehensive geometry vocabulary quiz designed to help students master terms like polygon, vertex, and various triangle types.

Explanation:
Let’s go step by step and match each vocabulary word with its correct definition from the list (numbered 1–24). We’ll use basic geometry knowledge.

1. polygon → Definition 15: *A closed plane figure made up of line segments.* ✔
(Any shape with straight sides, closed.)

2. vertex → Definition 7: *Two rays that have the same endpoint.* ✘ Wait — no! That describes an angle, not a vertex. Let’s fix:
Actually, vertex is *the common endpoint of the two rays in an angle* → Definition 19. ✔
So: vertex ↔ 19.

3. triangle → Definition 21: *A polygon with 3 sides.* ✔

4. quadrilateral → Definition 16: *A polygon with 4 sides.* ✔

5. pentagon → Definition 24: *A polygon with 5 sides.* ✔

6. parallelogram → Definition 22: *A quadrilateral with both pairs of opposite sides parallel.* ✔
(Note: definition 18 says “parallelogram with all sides same length” — that’s a rhombus; 17 is rectangle.)

7. square → Definition 1: *A rectangle with all sides the same length.* Also fits 17 (*parallelogram with four right angles*) + 18 (*all sides same length*), but only one match allowed.
However, definition 1 specifically says “a rectangle with all sides same length” — that’s the textbook definition of a square. So square ↔ 1.
But wait — definition 17 is *a parallelogram with four right angles* = rectangle.
Definition 18 is *a parallelogram with all sides same length* = rhombus.
Square = both rectangle and rhombus → but only one definition can be used per word. Since definition 1 explicitly says “rectangle with all sides same length”, and that uniquely defines square, we assign square ↔ 1.

8. hexagon → Definition 20: *A polygon with 6 sides.* ✔

9. acute triangle → Definition 3: *A triangle whose angles are all acute angles.* ✔

10. right triangle → Definition 8: *A triangle in which one angle is a right angle.* ✔

11. obtuse triangle → Definition 6: *A triangle in which one angle is an obtuse angle.* ✔

12. isosceles triangle → Definition 9: *A triangle with two sides of the same length.* ✔

13. scalene triangle → Definition 13: *A triangle in which no sides have the same length.* ✔

14. equilateral triangle → Definition 11: *A triangle whose sides all have the same length.* ✔

15. protractor → Definition 12: *An instrument used to measure and draw angles.* ✔

16. angle → Definition 19 is already used for vertex. Wait — let’s list all definitions and cross-check usage.

Let’s make a table of definitions and find unique matches:

Definitions:
1. A rectangle with all sides same length → square
2. An angle whose measure is exactly 180° → straight angle
3. Triangle with all acute angles → acute triangle
4. Quadrilateral with exactly one pair of parallel sides → trapezoid
5. Angle between 0° and 90° → acute angle
6. Triangle with one obtuse angle → obtuse triangle
7. Two rays with same endpoint → actually describes angle, but definition 19 says: *The common end point of the two rays in an angle* → that’s vertex
8. Triangle with one right angle → right triangle
9. Triangle with two equal sides → isosceles triangle
10. Angle = 90° → right angle
11. Triangle with all sides equal → equilateral triangle
12. Instrument to measure/draw angles → protractor
13. Triangle with all sides different → scalene triangle
14. Angle between 90° and 180° → obtuse angle
15. Closed plane figure of line segments → polygon
16. Polygon with 4 sides → quadrilateral
17. Parallelogram with 4 right angles → rectangle
18. Parallelogram with all sides same length → rhombus
19. Common endpoint of two rays in an angle → vertex
20. Polygon with 6 sides → hexagon
21. Polygon with 3 sides → triangle
22. Quadrilateral with both pairs of opposite sides parallel → parallelogram
23. Polygon with 8 sides → octagon
24. Polygon with 5 sides → pentagon

Now assign each word:

- polygon → 15
- vertex → 19
- triangle → 21
- quadrilateral → 16
- pentagon → 24
- parallelogram → 22
- square → 1
- hexagon → 20
- acute triangle → 3
- right triangle → 8
- obtuse triangle → 6
- isosceles triangle → 9
- scalene triangle → 13
- equilateral triangle → 11
- protractor → 12
- angle → ??? Wait — “angle” is a general term. Which definition fits?
Definitions left unused: 2, 5, 10, 14, 17, 18, 23
Words left: angle, obtuse angle, acute angle, straight angle, right angle, rectangle, rhombus, octagon, trapezoid

Let’s list remaining words and match:

- angle → general term; but none of the definitions say just “angle”. However, definition 7 says: *Two rays that have the same endpoint.* That is the definition of an angle (geometrically, an angle is formed by two rays sharing a vertex). So angle ↔ 7.
Then vertex must be 19 (common endpoint), which is correct.

So update:
- angle → 7
- vertex → 19

Now:
- obtuse angle → 14 (between 90° and 180°) ✔
- acute angle → 5 (between 0° and 90°) ✔
- straight angle → 2 (exactly 180°) ✔
- right angle → 10 (exactly 90°) ✔
- rectangle → 17 (parallelogram with 4 right angles) ✔
- rhombus → 18 (parallelogram with all sides same length) ✔
- octagon → 23 (8 sides) ✔
- trapezoid → 4 (quadrilateral with exactly one pair of parallel sides) ✔

Now verify all 24 words are matched:

Words list (24 items):
1. polygon → 15
2. vertex → 19
3. triangle → 21
4. quadrilateral → 16
5. pentagon → 24
6. parallelogram → 22
7. square → 1
8. hexagon → 20
9. acute triangle → 3
10. right triangle → 8
11. obtuse triangle → 6
12. isosceles triangle → 9
13. scalene triangle → 13
14. equilateral triangle → 11
15. protractor → 12
16. angle → 7
17. obtuse angle → 14
18. acute angle → 5
19. straight angle → 2
20. right angle → 10
21. rectangle → 17
22. octagon → 23
23. rhombus → 18
24. trapezoid → 4

All definitions 1–24 used exactly once. Perfect.

Final matching (write numbers beside each word):

polygon → 15
vertex → 19
triangle → 21
quadrilateral → 16
pentagon → 24
parallelogram → 22
square → 1
hexagon → 20
acute triangle → 3
right triangle → 8
obtuse triangle → 6
isosceles triangle → 9
scalene triangle → 13
equilateral triangle → 11
protractor → 12
angle → 7
obtuse angle → 14
acute angle → 5
straight angle → 2
right angle → 10
rectangle → 17
octagon → 23
rhombus → 18
trapezoid → 4

Final Answer:
15, 19, 21, 16, 24, 22, 1, 20, 3, 8, 6, 9, 13, 11, 12, 7, 14, 5, 2, 10, 17, 23, 18, 4