Question

22. The area of a trapezium is 12 cm2. and its height is 3
cm. If one of the parallel side is 3 cm, what will be
the length of the other side ?
​

Answer 1

Answer:

here

area= 12cm²

one side =3cm

height=3cm

another side = x

so,

area of trapezium =1/2 ( sum parallel side)h

12cm²= 1/2(3+x)3

( 12)2= 9+3x

24 - 9= 3x

15= 3x

5= x

hence , another side is 5

Answer 2

Given :-

• area of the trapezium = 12 cm²
• height of the trapezium = 3 cm
• parallel side of the trapezium = 3 cm

To Find :-

• length of the other side ?

Solution :-

we know that, it ‘a’ and ‘b’ are two parallel sides and ‘h’ is the height of the trapezium, then

$\boxed{ \bold{area \: of \: trapezium = \frac{1}{2} (a + b) \times h}}$

$\bold{: \implies \frac{1}{2} \times (3 + b) \times 3} = 12 \\ \\ \bold{: \implies3 + b = \frac{ \cancel{12} \times 2}{ \cancel3} } \: \: \: \: \: \: \: \: \: \: \\ \\ \bold{: \implies 3 + b = 4 \times 2} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \bold{: \implies 3 + b = 8}\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \bold{: \implies b = 8 - 3}\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \bold{: \implies b = 5}\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

hence, length of the other parallel side is 5 cm