Cogito
Geometry · Chapter 8 · Lesson 3
Cross Sections and Cavalieri
Slicing a solid, and why a leaning stack holds its volume.
11 problems · about 23 minutes · G-GMD.A.1, G-GMD.B.4
Figure — use these to answer the problems
Cylinder
Flat faces
2
Does it roll?
Yes
Warm Up
Straightforward practice. Get the method working first.
4 problemsA sphere sliced any way. How many sides? Use 0 for a curve.
AnswerA cube sliced parallel to a face. How many sides has the cross section?
AnswerA sphere sliced any way. How many sides? Use 0 for a curve.
AnswerA cone sliced horizontally. How many sides? Use 0 for a curve.
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsDoes leaning a stack change its volume? 1 for yes, 0 for no.
AnswerMatch each solid to the cross section of a horizontal slice.
Draw a line from each item on the left to its match on the right.
- Cylinder
- Cube
- Triangular prism
- Circle
- Square
- Triangle
A cylinder sliced at a slant. Circle or ellipse? 1 for circle, 2 for ellipse.
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsCavalieri needs the two solids to share what? 1 for height, 2 for weight.
AnswerTwo prisms, same base area and height. Same volume? 1 for yes, 0 for no.
AnswerThe Slice
A cylinder sliced horizontally. How many sides has the cross section? Use 0 for a curve.
AnswerThe Lean
A leaning prism and an upright one, same height and cross sections. Same volume? 1 for yes, 0 for no.
Answer