Question

The area of a trapezium is 480 cm², the distance between two parallel sides is 15 cm and one of the parallel side is 20 cm. The other parallel side is:​

Answer 1

Solution :

Let us assume that the other parallel side of the trapezium is x cm.

One of the given parallel sides is 20 cm.

The corresponding perpendicular distance between the parallel sides is 15 cm.

So, the area of the given trapezium becomes :

> 1/2 * ( Sum of parallel sides) * ( Perpendicular distance between them )

> 1/2 * ( x + 20 ) * ( 15 )

But , the area of the trapezium is 480 cm^2 .

Hence,

1/2( x + 20) * 15 = 480

> 15(x+20) = 960

> x + 20 = 64

> x = 44 cm.

This is the required answer.

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Answer 2

Given:

The area of a trapezium = 480 $cm^{2}$, the distance between two parallel sides = 15 cm and one of the parallel side = 20 cm

Let the other parallel side = x

We have to find, the value of other parallel side.

Solution:

We know that,

The area of a trapezium = $\dfrac{1}{2}$ × (Sum of parallel sides) × (Distance between them)

∴ $\dfrac{1}{2}$ × (20 cm + x) × (15 cm) = 480 $cm^{2}$

⇒ 20 + x = $\dfrac{480\times 2}{15}$ cm

⇒ 20 + x = 32 × 2 cm

⇒ x = 64 - 20 cm

⇒ x = 44 cm

∴ The other parallel side of a trapezium = 44 cm

Thus, the other parallel side of a trapezium is "44 cm".