D

INNOVATIVE LESSON TEMPLATE

Name of the teacher:Anju Krishna .R.S Standard:ixName of the School :SNVHSS Nedunganda Division:A Subject : Mathematics Strength: Unit : Area Duration:Subunit :Area of a quadrilateral Date:Curricular Objectives To understand how to compute the area of a quadrilateral by dividing it into two triangles in between two parallel lines.Content AnalysisContent : The idea behind dividing the quadrilateral.In between two parallel lines into triangles.Fact: A quadrilateral can be devided into two triangles.Learning outcomesThe pupil will be able to(i) Retrieve the idea of aea of quadrilateral(ii) Recall the idea behind triangle between two parallel lines.(iii) Execute the above concept in new situation.(iv) Judge the appropriateness of the given problem.(v) Performing geometrical skillsPre-requistiesThe pupil knows(i) Area of triangle(ii) Area of triangle between two parallel lines are equalSupporting Materials(i)Chart cuttings(ii) Chart showing figures based on the concept

Interaction Procedure Actual ResponseThe teacher begins the class askin g question.How do we find the area of a quadrilateral? [by drawing a diagonal, we can divide the quadrilateral into two triangles. Then by finding the area of these two triangles and add them, so that we get the area of the quadrilateral] (recalls)Then the teacher draws a quadrilateral and divide it into two triangles, by drawing a diagonal. C

D

A BWe have learned this method of finding the area of quadrilateral in our preuious classes. Now, we can find this by a new method.Remember how we compute the area of a quadrilateral (Confusion)

The teacher then show a chart paper cutting of a quadrilateral ABCD D C

AB

How can we make it into two triangles? [Draw the diagonal BD] (Recalls)Then the teacher draws the diagonal BD and divided it into two triangles.Without changing the area of ABCD, can we join it with Abd and make it a large triangle?(Confusion)The teacher draws it in blackboard. C D

AEBNow what will be the area of the qualdrilateral ABCD?(Sum of the areas of ABD and BDE(identifies)How we can say it more clearly?(Area of the quadrilateral ABCD is equal to the area of the large triangle AED] (identifies)

How we can realize it ? (Confusion)CThe teacher then shows a chart. D

P ABWhat you can observe in that figure[Draws a line parallel to the side BD, through the vertex C] (identifies)What we can say from this?[ABCD and BDP are equal area ] (identifies)Now what we can say about the area of the quadrilateral?[The quadrilateral ABCD and ABPD also have equal area] (identifies)We have to make this quadrilateral into a large triangle. How can we make it ?(Confusion)Then the teacher shows another chart containing the figure.C

D

A B E

What can you observe in this figure?[The parallel line through C, cuts AB at E Also, another triangle bde is drawn by taking E as the third vertex] (identifies)Is there any relation between the area of BDE and BDC? [Yes] (identifies)What?[Area are equal] (recognize)Why?[BDE and BDC lies between the parallel lines BD and CE] (recognize)Then what will be the area of the quadrilateral ABCD?[It must be equal to the area of ADE]What we have drawn her?[We have transformed the quadrilateral ABCD into the triangle BDC without attering its area] (identifies)Review and ApplicationLike this draw a line parallel to the diagonal AC,through the point D and then drqw another triangle.What we have to do/[We have to draw a triangle, having the same area as that of the quadrilateral ABCD, parallel to the diagonal AC]What we have to do first?[Draw the diagonal AC] (draws)What we have to do next?[Draw a line parallel to AC, through D and meat the point P and then draw the triangle APB](identifies)Then the teacher draw it on blackboard. P

C

A B

What we have to do next?[Extend AB to meet at the parallel line][Then chose that point as the third vrtex and then draw the triangle][draws] D

C

E AB

Which is the triangle, having the same area as that of the quadrilateral[BEC] (identifies)Follow up ActivityDraw a quadrilateral ABCD and make it into triangle having equal area as that of the quadrilateral.

]