Season 2 • Episode 15 • Cross sections of a tetrahedron
0Cross sections of a tetrahedron
Season 2
Episode 15
Time frame 1 period
Objectives :
•
Disover the onept of ross setion of a solid.•
Review the oneptq of ollinearity and oplanarity in3D.•
Study the possibleross setionsof a tetrahedron.Materials :
•
Six opies of six dierent problems.•
One answersheet for eahstudent.•
Beamer.1 – Introduction 5 mins
The teaher introdues the onept of ross setion, with a beamer. The examples given
are the ross setionsofasphere, that are alwaysirles.Then, the planof thehapteris
given : tetrahedron,ube and one.
2 – Individual work 10 mins
Eah student is given a problem about how to ut a tetrahedron to get a ertain ross
setion shape.
3 – Group work Remaining time
Studentsmingletoformsixgroupsofsixpeoplewithdierentproblems.Theyexplainand
hek eahother'sanswertolloutananswersheet withthe answers tothe sixproblems.
At the end of the hour, eahgroup has to hand out tothe teaher the six answer sheets.
These six answer sheets are then marked and graded. If the 6 answer sheets of a group
Cross sections of a tetrahedron
Season 2
Episode 15
Document Answer sheet
Problem 1
The cross section is . . . .
b A
b
B
b
C
b D
Problem 2
The cross section is . . . .
b A
b
B
b
C
b D
Problem 3
The cross section is . . . .
b A
b
B
b
C
b D
Problem 4
The cross section is . . . .
b A
b
B
b
C
b D
Problem 5
The cross section is . . . .
b A
b
B
b
C
b D
Problem 6
The cross section is . . . .
b A
b
B
b
C
b D
Season 2 • Episode 15 • Cross sections of a tetrahedron
2Document 1
Six ross setion problemsProblem 1 : Find a way to ut a regular tetrahedron so
that the ross setion is an equilateral triangle.
Problem 2 : Find a way to ut a regular tetrahedron so
that the ross setion is an isoseles triangle, an not an
equilateral one.
Problem 3 : Find a way to ut a regular tetrahedron so
that the ross setion is a salene triangle.
Problem 4 : Find a way to ut a regular tetrahedron so
that the ross setion is a square.
Problem 5 : Find a way to ut a regular tetrahedron so
that the ross setion is a retangle and not a square.
Problem 6 : Find a way to ut a regular tetrahedron so
