The area of a trapezium is `180\ c m^2` and its height is 12cm. If one of the parallel sides is double that of the other, find the two parallel sides.

Explanation

Given
area of trpezium `=180cm^2` and height `=12cm` .
If one of the parallel sides is double that of the other then we need to find parallel sides.
Now , let the smaler parallel side be` x `.
then other parallel side`=2x` .now we know that area of trapezium `=(1/2)xx`(sum of parallel sides)`xx`height. now, putting the known values ,we get.
`180=[(x+2x)/2]xx12`
`implies (x+2x)/2=180/12`
`implies (x+2x)/2=15`
`implies x+2x=30`
`implies 3x=30`
`implies x=30/3=10`.
Hence one of the parallel sides `=10cm` while the other parallel side`=2xx10=20cm`.