Question

a trapezium with parallel sides length as 7 :3 is cut from the a rectangle 30dm by 4dm so as to have an area of one third lhe latter. find the length of the parallel sides

Answer 1

Answer:

a=18.6 dm and b= 8 dm

Step-by-step explanation:

Given Length of the Rectangle = ab=40 dm and breadth of the rectangle = bc = 3 dm

therefore area of the rectangle = $40\times3=120$ dm²

The area of the trapezium = 1/3 of the area of the rectangle = 40 dm²

Consider the length of the parallel side of the trapezium are 7x and 3x

we know that the area of trapezium = $h\times(\frac{a+b}{2})$

where h = height of the trapezium

a and b are the two side.

therefore

$40=3\times(\frac{7x+3x}{2})\\\\40=3\times(\frac{10x}{2})\\\\40=3\times5x\\\\40=15x\\\\x=\frac{40}{15}$

Puting the value of x we get the length of the two side are

$a=7\times\frac{40}{15}=18.6 dm$ and $b=3\times\frac{40}{15}= 8 dm$