Difference between revisions of "Deriving formula for area of a trapezium"
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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. |
Revision as of 11:33, 30 May 2019
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
- 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
- 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:
- Write down the steps involved in deriving the formula for area of trapezium.