Class 08 Activity – Understanding Quadrilaterals

Objective:

 To make the following by paper folding and cutting.(a) Kite (b) Rhombus

Materials Required:

 White sheets of paper, a pair of scissors, glue stick, geometry box, etc.

Procedure: 

(a) To make a kite

1. Take a white sheet of paper and fold it once from the middle as shown below.

2. Draw two line segments AB and BC of different lengths as shown.

3. Cut along the line a segments AB and BC and unfold the cut –out . Draw a dotted line along the  fold and mark the two other vertices as C and D.

(b) To make a rhombus

Take a sheet of paper and fold it from the middle as shown below. 

2. Draw two line segments AB and BC such that AB = BC as shown.

3. Cut along the line segments AB and BC and and unfold the cut out. Draw a dotted line along the fold and mark the two other vertices as C and D.

Observations:

On measuring the sides AB, BC, CD and DA in figure 3, we find that AB = AD and BC = DC.

Hence, ABCD in figure 3 is a kite.

2. On measuring the sides AB, BC, CD and AD in figure, we find that AB = BC = CD = AD.

Hence, ABCD  in figure 6 is a rhombus.

Class 08 Activity – Understanding Quadrilaterals

 Based on CHAPTERs8. Comparing Quantities13. Direct and Inverse Proportions3. Understanding Quadrilaterals4. Practical Geometry

Activity – Understanding Quadrilaterals

Objective: 

To verify that the sum of the interior angles of a quadrilateral is 360 ° by paper cutting and pasting.

Materials Requried:

 White sheets of paper, colour pencils, a pair of scissors, gluestick, geometrybox, etc.

Procedure:

1. On a white sheet of paper, draw a quadrilateral ABCD. Colour its angles as shown. 

2. Using a pair of scissors, cut out the angular regions as shown below.

3. Mark a point 0 on a sheet of paper. Paste the four angular cut-outs so that the vertex of each falls at O, as shown in the figure.

Observations: 

In figure, we see that the angular cut-outs neither overlap nor leave any gap between them, i.e., the angles together form a complete angle.

∠A + ∠ B + ∠ C + ∠ D = a complete angle = 360 °

or sum of the angles of a quadrilateral is 360 °

Conclusion:

 From the above activity, it is verified that the sum of the interior angles of a quadrilateral is 360 °

Do Yourself: 

On a white sheet of paper, draw three different quadrilaterals. 

In each case, verify the angle sum property of a quadrilateral by paper cutting and pasting.