Question

One of the parallel sides of a trapezium is thrice the other and the height is half the sum of the parallel sides.if the area of the trapezium is 400cmsq.find the lengths of its parallel sides

Answer 1

Let 1st parallel side = x
So, 2nd parallel side = 3x
So, height = (x + 3x)/2 = (4x)/2 = 2x

Now, area of trapezium = [Sum of parallel sides * height] /2
                                      = [(x + 3x) * 2x ]/2 
                                      = 4x²
But, area is given as 400 cm²
So,                          400 = 4x²
                                    x = √100
                                    x = 10
So sides = 10 cm & 30 cm respectively

Answer 2

Answer:

Step-by-step explanation:

Let 1st parallel side = x

So, 2nd parallel side = 3x

So, height = (x + 3x)/2 = (4x)/2 = 2x

Now, area of trapezium = [Sum of parallel sides * height] /2

                                     = [(x + 3x) * 2x ]/2 

                                     = 4x²

But, area is given as 400 cm²

So,                          400 = 4x²

                                   x = √100

                                   x = 10

So sides = 10 cm & 30 cm respectively########