The difference between two parallel sides of a trapezium is 4 cm. perpendicular distance between them is 19 cm. If the area of the trapezium is 475 find the lengths of the parallel sides.

Let the two parallel sides of the trapezium be a cm and b cm. 

Then, a - b = 4 

And,  $\frac{1}{2}\times a+b\times 19=475=>a+b=50$ 

Solving (i) and (ii), we get: a = 27, b = 23. 

So, the two parallel sides are 27 cm and 23 cm.