Explanation
In this page, we practice identifying whether something is \(1D, 2D,\) or \(3D\).
Remember:
\(1D\) means a line.
\(2D\) means a flat shape.
\(3D\) means a solid object.
We can also think about how many numbers are needed to locate a point:
\(1D\) → \(x\)
\(2D\) → \((x, y)\)
\(3D\) → \((x, y, z)\)
Formula / Rule
Use this rule:
\(1D\) → one direction → right or left
\(2D\) → two directions → right/left and up/down
\(3D\) → three directions → right/left, forward/backward, and up/down
Example 1
Classify a point on a number line.
A point on a number line needs only one number.
For example:
\(x = 5\)
So, a point on a number line is in:
\(1D\)
Example 2
Classify a rectangle.
A rectangle is a flat shape.
It has length and width.
It does not have depth or thickness.
So, a rectangle is:
\(2D\)
Example 3
Classify a circle.
A circle is a flat shape.
It can be drawn on a flat surface.
It has no depth.
So, a circle is:
\(2D\)
Example 4
Classify a sphere.
A sphere is like a ball.
It is a solid object in space.
It has length, width, and height.
So, a sphere is:
\(3D\)
Example 5
Classify the coordinate:
\(7\)
This coordinate has one number only.
So, it represents a point in:
\(1D\)
Example 6
Classify the coordinate:
\((3, 4)\)
This coordinate has two numbers.
The first number gives the \(x\)-coordinate, and the second number gives the y-coordinate.
So, it represents a point in:
\(2D\)
Example 7
Classify the coordinate:
\((2, 5, 1)\)
This coordinate has three numbers.
The numbers represent \(x, y, and \(z\).
So, it represents a point in:
\(3D\)
Practice
- More Examples (Current page)
- Take the Quiz
Continue Learning
- Length, Area, and Volume: What’s the Difference?
- Difference between \(1D, 2D,\) and \(3D\)
- \(3D, 4D,\) and Beyond in Real Life