The same – always a square!

FW 2.3: Slicing Pyramids and Prisms
Learning Target:
I will identify the two-dimensional shapes that can be
created from slicing three-dimensional shapes.
HW: Complete the SBAC Practice Test Part 2 and
Correct with the Zaption video: SBAC Practice Test Pt 2
Warm Up: Find the surface area and volume
of the hexagonal prism.
πŸ‘ π’„π’Ž
π΄π‘Ÿπ‘’π‘Ž π‘œπ‘“ π΅π‘Žπ‘ π‘’ = 𝟐𝟎 π’„π’ŽπŸ
πŸ“ π’„π’Ž
𝑺𝒖𝒓𝒇𝒂𝒄𝒆 𝑨𝒓𝒆𝒂 = 𝟐 𝟐𝟎 + πŸ” πŸ‘ × πŸ“
= πŸ’πŸŽ + πŸ” πŸπŸ“
= πŸ’πŸŽ + πŸ—πŸŽ
= πŸπŸ‘πŸŽπ’„π’ŽπŸ
π‘½π’π’π’–π’Žπ’† = 𝟐𝟎 × πŸ‘
= πŸ”πŸŽπ’„π’ŽπŸ‘
Review of Rectangular Prisms
Where is a vertex?
Where is an edge?
Where is a face?
Vertex
Edge
Face
Review of Rectangular Prisms
β€’ Why is it called a rectangular prism?
– The base of the prism is in the shape of a rectangle.
Prisms are named by their base.
β€’ How many faces does a rectangular prism have?
─ 6 faces
β€’ How many vertices does a rectangular prism have?
– 8 vertices
β€’ How many edges does a rectangular prism have?
– 12 edges
Vocab Toolkit
What are the different 2D shapes that you
can make by slicing a cube with one cut?
Triangle, square, rectangle, non-rectangular parallelogram, pentagon, hexagon
Math Shorts Video – Slicing 3D Figures
https://vimeo.com/82400980
After the video, turn and talk to your partner about the
different 2D shapes you can make from slicing a pyramid.
p. 6
The Cube: Using play-doh, create a model of a cube.
Using dental floss, slice through the middle of the cube in a direction perpendicular to the base.
Sketch how you sliced the cube and then sketch and
name the figure formed by the cross-section.
A square - the same shape!
If the slice was made in a different area
(but still perpendicular to the base),
would the shape of the cross-section
be the same or different?
The same – always a square!
β€’ Put the cube back together and slice through the middle of the cube in
a direction parallel to the base.
Sketch how you sliced the cube and then sketch and name
the figure formed by the cross-section.
Square
If the slice was made in a
different area (but still
parallel to the base),
would the shape of the
cross-section be the same
or different?
The same – always a square!
β€’ Put the cube back together and create a cross-section that would make a triangle shape.
Cut off a corner!
Did you notice…
β€’ When you make a cut through four faces, you make a four-sided shape (rectangle
or non-rectangular parallelogram).
β€’ When you make a cut through five faces, you make a five-sided shape (pentagon).
β€’ When you make a cut through six faces, you make a six-sided shape (hexagon).
Rectangular Prisms
Using play-doh, create a right rectangular prism that is not a cube. The bases of the prism are
squares and the lateral faces are rectangles.
Using dental floss, slice through the middle of the prism in a direction that is perpendicular to
the base (and parallel to the faces).
Sketch how you sliced the prism and then
sketch and name the figure formed by the
cross-section.
Rectangle
The same – always a rectangle!
Square
The same – always a square!
Slice off a corner.
Rectangle
Triangle
The same – always a rectangle!
The same – always a triangle!
Rectangle
Circle
The same – always a rectangle!
The same – always a circle!
Triangle
The same – always a triangle!
Square
The same – always a square!
Rectangle
Square
Triangle, non-rectangular prism, pentagon, hexagon
FW 2.3: Slicing Pyramids and Prisms
Did I reach my Learning Target?
I will identify the two-dimensional shapes that can be
created from slicing three-dimensional shapes.
HW: Complete the SBAC Practice Test Part 2 and
Correct with the Zaption video: SBAC Practice Test Pt 2