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10Transformations of Quadrilaterals Unit

4 . A rectangular piece of paper is folded twice, cut along the dotted line, 4. Have the students cut the rectangle sheet[A4]

and unfolded. What you need: Rectangle Sheet (A4), Scissors

to check if the sides of a rhombus are equal and

if the opposite angles are equal.

Fold the rectangle sheet twice. Cut the

diagonal as shown and unfold.

Fold the figure up in half to see if the halves

align perfectly.

Fold the figure to the right in half to see if the

Is the shape a rhombus? Explain why you think so. halves align perfectly.

Yes, the shape is a rhombus. The folding and cutting made all of the sides equal. Refer to .
Also, the shape has 2 pairs of parallel sides.

5. Have students find the missing measures.
First, have them find the opposite angle of the
missing angle.

5 . The figures below are rhombuses. Fill in the blanks. a. b.
5 cm
140 45
a. b.
8 cm
5 cm 45
140 140
8 cm 5 cm 45
8 cm

140 45 A rhombus has four equal sides and opposite
5 cm 8 cm
angles that are equal. The missing measure

can be found using this fact.

10. Transformations of Quadrilaterals 89

A rhombus has four equal sides Fold to the side and overlap the Result
Fold up and overlap the halves halves

ab ab

cd cd a b, c d, a c, b d
so, a b c d. The four sides
The halves align perfectly. This The halves align perfectly.This are equal.
shows that sides a and b are shows that sides a and c are
equal and sides c and d are equal and sides b and d are 4A Unit 10 145
equal. equal.