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If the area of a trapezium is 80 cm┬▓ and the parallel sides are 13.5 and 6.5 cm, then the distance between them (in cm) is ______.
8
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10
8
Calculate the average of the two parallel sides first: (13.5+6.5)/2=10. Then, simply divide the total area by this average: 80/10=8.
Area of trapezium = 80 cm┬▓, Parallel side a = 13.5 cm, Parallel side b = 6.5 cm.
Area=21тАЛ├Ч(a+b)├Чh
Calculate the average of the two parallel sides first: (13.5+6.5)/2=10. Then, simply divide the total area by this average: 80/10=8.
Students often forget to include the '1/2' factor in the trapezium area formula or miscalculate the sum of the parallel sides.
Identify the given values
Given the area A=80, parallel sides a=13.5, and b=6.5. We need to find the height h.
A=80,a=13.5,b=6.5
Apply the Trapezium Area Formula
Substitute the known values into the standard area formula for a trapezium.
80=21тАЛ├Ч(13.5+6.5)├Чh
Simplify and Calculate
Sum the parallel sides: 13.5+6.5=20. Then, solve for h: 80=10├Чh, so h=8.
80=21тАЛ├Ч20├ЧhтЗТh=1080тАЛ=8
A is correct because the calculation h=80/(20/2) results in 8 cm.
This concept of finding a dimension given area is fundamental in Mensuration and Coordinate Geometry (e.g., finding the distance between lines).