Download OBJECTIVES: To classify triangles using criteria such a equal sides

OBJECTIVES: To classify triangles using criteria such as equal sides and equal angles.
To know some properties about triangles such as the measure of its angles.
FOCUS: CLASSIFYING TRIANGLES AND MEASURING.
UNIT: 2
LESSON: 3
COMMUNICATION
LANGUAGE OF LEARNING

Vocabulary of the topic
Vocabulary U2 L1, U2 L2(start)
regular/irregular polygons
circle
semi-circle
oval
triangle
pentagon
hexagon
heptagon
octagon
two-dimensional
shape
flat
straight lines
curved lines
closed figures
vertex/vertices
side
angle
LANGUAGE FOR LEARNING

Language instruction
Start playing a domino game (worksheet 2.4).
Ask children, in groups of two, to reproduce on the geoboard all the possible
triangles and draw them on the dot paper.
Encourage children to discuss about possible ways to classify triangles.
Ask them to look carefully at their booklet for U2 L3 and listen to the
teacher’s explanation.
Ask children to cut out the triangles and stick them in the right place
(worksheet 2.5).
Draw a triangle on a piece of paper and rips off the three corners.

Questions for learning
What can you say about triangles,..?
How can you classify triangles?
How can you be sure if two triangles
you drew are equal?
Did you find any concave? Why?
Did you find any triangle with two
right-angles? Why?
Is there any triangle with two obtuse
angles? Why?
Is there any triangle with three acute
angles? Why?
What’s the sum of the3 angles?

Sentences for answering
A triangle ……
Depending on the sides/on the angles
Probably measuring them/ cutting
and overlap them.
No, because……..
No, I didn’t. Because it would not be
a triangle.
No, there isn’t. . Because it would
not be a triangle.
Yes, there is. Because we can draw a
three side shape with three acute angles.
It can be……..
LANGUAGE THROUGH
LEARNING
 Language that comes
through the lesson
polygon
convex
concave
Triangles’ classification(main
teaching)
Right-angle
Obtuse
Acute
Isosceles
Scalene
Equilateral
Measuring vocabulary(ending)
Protractor
Degrees
Sum

Language to express conclusions
“A triangle has 3 sides and 3 angles.”
“A triangle cannot have 2 right angles or 2 obtuse angles, but it can have 3
acute angles.”
“The sum of the three angles of a triangle is always 180º.”
Triangles’ classification:
When looking at the lengths of sides:
“Equilateral Triangle: A triangle having all three sides of equal length. The
angles of an equilateral triangle all measure 60 degrees.
Isosceles Triangle: A triangle having two sides of equal length.
Scalene Triangle: A triangle having three sides of different lengths.”
When looking at the size of the largest internal angle:
“Acute Triangle: A triangle having three acute angles.
Obtuse Triangle: A triangle having an obtuse angle. One of the angles of the
triangle measures more than 90 degrees.
Right angle Triangle: A triangle having a right angle. One of the angles of
the triangle measures 90 degrees. “
RESOURCES: Booklet U2 L1, Booklet U2 L3, geoboard, elastic bands, dot paper, scissors, glue, worksheets: 2.4,2.5,2.6,, Power Point, websites.
http://www.eyepleezers.com/aaamath/geo612x5.htm