This document defines and describes basic geometric shapes and terms including points, lines, planes, angles, triangles, quadrilaterals like squares and rectangles, circles, spheres, cylinders, cubes, and polygons with specific numbers of sides. Key geometric concepts covered are parallel and perpendicular lines, right triangles, and the defining characteristics of common two- and three-dimensional shapes.

1. Geometry in the Real World
By Sam Spoonemore Block 1

2. Point
• An undefined term in geometry, it names a
location and has no size.

3. Line (Segment)
• A part of a line that is bounded by two end
points, and contains every point on the
line between its end points.

4. Plane
• An undefined term in geometry, it is a flat
surface that has no thickness and extends
forever.

5. Angle
• A figure formed by two rays with a
common endpoint.

6. Perpendicular Lines
• Lines that intersect at 90° angles.

7. Parallel Lines
• Lines in the same plane that do not
intersect.

8. Triangle
• A three-sided polygon.

9. Right Triangle
• A triangle with one right angle.

10. Pentagon
• A five-sided polygon.

11. Hexagon
• A six-sided polygon.

12. Square
• A quadrilateral with four congruent sides
and four right angles.

13. Rectangle
• A quadrilateral with four right angles.

14. Trapezoid
• A quadrilateral with exactly one pair of
parallel sides.

15. Parallelogram
• A quadrilateral with two pairs of parallel
sides.

16. Circle
• The set of points in a plane that are a fixed
distance from a given point called the
center of the circle.

17. Cylinder
• A three-dimensional figure with two
parallel congruent circular bases and a
curved lateral surface that connects the
bases.

18. Sphere
• The set of points in space that are a fixed
distance from a given point called the
center of the sphere.

19. Octagon
• An eight-sided polygon.

20. Cube
• A prism with six square faces.

21. Hemisphere
• Half of a sphere.