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118_G4U10_TG_CA 2014.4.21 12:47 PM ˘ ` 140
Activity 1 Parallelograms
jOb ective Learn about and understand parallelograms and their properties.
1. Textbook Instructions Activity 1 Paralellograms Anglegs
Learn about parallelograms. 1 . Push one corner of a rectangle to change its shape.
What you need:
1. First, have the students use two types of A quadrilateral with 4 right
Anglegs to make a rectangle. Have them push angles and 2 pairs of parallel
down one corner of the rectangle and observe sides is called a rectangle.
how the rectangle changes its shape.
Have the students look for the similarities in A quadrilateral with 2 pairs
the original rectangle and the new figure. of parallel sides is called a
parallelogram. Opposite sides
Side length: The length of both pairs of of parallelograms are equal.
opposite sides in both figures are the same.
Number of opposite sides that are parallel:
Both figures have two pairs of opposite
sides.
So, both figures have two pairs of
opposite sides that are parallel and have
equal lengths.
Tell the students that figures with two pairs of What shape is made by pushing one corner of the rectangle?
parallel sides are called parallelograms. Explain why you think so.
Have the students also look for the differences A parallelogram is made by pushing one corner of the rectangle.
The shape made has 2 pairs of parallel sides, and opposite sides are equal.
in the two figures.
84
Refer to .
2. Build Understanding
Differences when a rectangle is made into a parallelogram
A rectangle has four right angles. When one corner is pushed down, the angles either become less than
or greater than 90 . The new figure no longer has right angles.
a d a' d' Angles a and c The angles that were 90 ,
are greater than 90 in the new figure.
Angles b and d The angles that were 90 ,
b c b' c' are less than 90 in the new figure
140 NUMINO Teacher s Guide
Activity 1 Parallelograms
jOb ective Learn about and understand parallelograms and their properties.
1. Textbook Instructions Activity 1 Paralellograms Anglegs
Learn about parallelograms. 1 . Push one corner of a rectangle to change its shape.
What you need:
1. First, have the students use two types of A quadrilateral with 4 right
Anglegs to make a rectangle. Have them push angles and 2 pairs of parallel
down one corner of the rectangle and observe sides is called a rectangle.
how the rectangle changes its shape.
Have the students look for the similarities in A quadrilateral with 2 pairs
the original rectangle and the new figure. of parallel sides is called a
parallelogram. Opposite sides
Side length: The length of both pairs of of parallelograms are equal.
opposite sides in both figures are the same.
Number of opposite sides that are parallel:
Both figures have two pairs of opposite
sides.
So, both figures have two pairs of
opposite sides that are parallel and have
equal lengths.
Tell the students that figures with two pairs of What shape is made by pushing one corner of the rectangle?
parallel sides are called parallelograms. Explain why you think so.
Have the students also look for the differences A parallelogram is made by pushing one corner of the rectangle.
The shape made has 2 pairs of parallel sides, and opposite sides are equal.
in the two figures.
84
Refer to .
2. Build Understanding
Differences when a rectangle is made into a parallelogram
A rectangle has four right angles. When one corner is pushed down, the angles either become less than
or greater than 90 . The new figure no longer has right angles.
a d a' d' Angles a and c The angles that were 90 ,
are greater than 90 in the new figure.
Angles b and d The angles that were 90 ,
b c b' c' are less than 90 in the new figure
140 NUMINO Teacher s Guide
