Question

Area of a rectangular plot is 1620 sq meter. If its length is 9 meter greater than breathe. Find length of plot.​

Answer 1

Given :-

Area of a rectangular plot is 1620 sq meter. If its length is 9 meter greater than breadth

To Find :-

Length

Solution :-

Let the breadth be b

Then, length will be b + 9

Area = l × b

1620 = (b + 9)b

1620 = b² + 9b

0 = b² + 9b - 1620

0 = b² + (45b - 36b) - 1920

0 = b² + 45b - 36b - 1920

0 = b(b + 45) - 36(b + 45)

0 = (b + 45)(b - 36)

Either

b + 45 = 0

b = -45

Or,

b - 36 = 0

b = 36

As the length can't be negative. So, we will neglect -45

Length = 36 + 9 = 45 m

Answer 2

Given :-

the area of rectangle plot is 1620sq meter

and length is 9m

To find :-

length

formula :-

Area = l × b

now,

Let the breadth be b

Then, length will be b + 9

Area = l × b

→ 1620 = (b + 9)b

→1620 = b² + 9b

→0 = b² + 9b - 1620

→0 = b² + (45b - 36b) - 1920

→0 = b² + 45b - 36b - 1920

→0 = b(b + 45) - 36(b + 45)

→0 = (b + 45)(b - 36)

→b + 45 = 0

→b = -45

→b - 36 = 0

→b = 36

As length can't be negative. So,

Length = 36 + 9 = 45 m

so therefore our required answer is 45m