the area of a trapezium is 385 cm². Its parallel side are in ratio 3:4 and the perpendicular distance between them is 11 cm. Find the lengths of its parallel sides.

Dear Student,
Let parallel sides be 3x and 4x.
Area of trapezium =(1/2)×Sum of parallel sides×height 
Area=(1/2)×(3x+4x)×11
385=(1/2)×7x × 11
7x=70
x=10
So, length of parallel sides are 30cm and 40cm.
Regards!