Question

17. The perimeter of a rectangle is 60 cm and the
area is 200 cm. Find the length?​

Answer 1

Answer:

let the length be x and the breadth be 2x

according to question:

perimeter of rectangle- 60 cm

2(l+b) =60cm

2(x+2x) =60cm

2×3x=60cm

6x=60cm

x=60/6

x=10 cm

length-10 cm, breadth-10×2=20cm

Answer 2

Answer:perimeter of rectangle=60cm and area of rectangle=200cm^2(given)

So;

2(Length+breadth)=60cm

Length +breadth=60/2=30cm

So,length=30-length........eqn(i)

Now,

Area=length×breadth

200cm^2=length×breadth

So,

Length=200cm^2/breadth........eqn(ii)

From eqn (i)&(ii)

200cm^2/b=30-b [breadth=b&length=l]

200=30b-b^2

b^2-30b+200=0

b^2-10b-20b+200=0

b(b-10)-20(b-10)=0

(b-10)(b-20)=0

So,b=10cm or 20cm

From eqn (i)

When b=10cm then,l =20cm

Or, when b=20cm then,l =10cm

Hence, length of rectangle= 10cm or 20cm