1. Cross Sections of Three-Dimensional Figures
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2. 3-Dimensional figures can be cut by planes
3-Dimensional figures can be cut by planes. When you cut a 3-D figure by a plane, the result is a 2-D figure.
The cross-sections of 3-D figures are 2 dimensional figures you are familiar with.
Look at the example on the next page to help your understanding.

3. A horizontal cross-section of a cone is a circle.
Can you describe a vertical cross-section of a cone?

4. A vertical cross-section of a cone is a triangle.

5. A water tower is built in the shape of a cylinder.
How does the horizontal cross-section compare to the vertical cross-section?

6. The horizontal cross-section is a circle.
The vertical cross-section is a rectangle

7. Which figure has the same horizontal and vertical cross-sections?9
Which figure has the same horizontal and vertical cross-sections? A C B D
Answer: C

8. Which figure does not have a triangle as one of its cross-sections? 10B D
Answer: C

9. Which is the vertical cross-section of the figure shown?11
Which is the vertical cross-section of the figure shown? A
Triangle B
Circle C
Square
Answer: C D
Trapezoid

10. Which is the horizontal cross-section of the figure shown?12
Which is the horizontal cross-section of the figure shown? A
Triangle B
Circle C
Square
Answer: C D
Trapezoid

11. Which is the vertical cross-section of the figure shown?13
Which is the vertical cross-section of the figure shown? A
Triangle B
Circle C
Square
Answer: A D
Trapezoid