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− | | + | ===Learning objectives=== |
| + | #The trapeium contains two parallel sides and two non-parallel sides. |
| + | #The area of trapezium is found by viewing it as a parallelogram. |
| + | #The area of trapezium is 1/2(a+b)h where a and b are its parallel sides and h is the perpendicular distance between them. |
| + | #The perimeter of a trapezium is obtained by sum of its 4 sides. |
| + | ===Notes for teachers=== |
| + | #The area of most figures can be expressed in terms of its dimensions. |
| + | #The area of most composite figures can be calculated using the area of primary figures. |
| + | ===Activity No # 1.Deriving formula for area of a trapezium=== |
| + | {| style="height:10px; float:right; align:center;" |
| + | |<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div> |
| + | |} |
| + | *Estimated Time: 20 minutes. |
| + | *Materials/ Resources needed : Laptop, geogebra file, projector and a pointer. |
| + | *Prerequisites/Instructions, if any |
| + | #The students should know a parallelogram and formula to find its area. |
| + | #They should know the trapezium and its properties. |
| + | *Multimedia resources: Laptop |
| + | *Website interactives/ links/ / Geogebra Applets: This geogebra file has been taken from :www.geogebratbe.org |
| + | <div id="ggbContainerd9759c2a6f0efea1b263d9f520270a06"></div> |
| + | *Process: |
| + | #The teacher can initially discuss about a trapezium. |
| + | #She can then reiterate that formula for area of certain composite figures can be found by converting them into known simple figures. |
| + | #Here the trapezium is converted into a parallelogram. |
| + | #Area of parallelogram is then deduced. |
| + | *Developmental Questions: |
| + | #What is a trapezium ? |
| + | #Name its two parallel sides. |
| + | #What is meant by the height of the trapezium ? |
| + | #After cutting the trapezium exactly in the centre what would be the new height ? |
| + | #What is the length of the new parallelogram formed ? |
| + | #What is the formula to find the area of a parallelogram ? |
| + | #What is the area of this parallelogram formed from a trapezium ? |
| + | *Evaluation: |
| + | #Explain the sequence of steps involved in deriving the formula for the area of a trapeium. |
| + | *Question Corner: |
| + | <span> </span> |
| + | #Write down the steps involved in deriving the formula for area of trapezium. |