The ratio between the length and breadth of a rectangular field is 5:4. If the breadth is 20 meters less than the length, the perimeters of the field is?

Let breadth = b meters.
then, length = 3b/2 meters
? b x 3b/2 = 2/3 X 10000
? b² = (4 x 10000)/9
? b = ( 2 X 100)/3 m
? Length = (3/2) x (2/3) x 100 m
= 100 m

Area = 1440 / 160 hectares
= 9 hectares
= 90000 m²

? One side = ?90000 m
= 300 m

So perimeter = 4 x 300 m
= 1200 m

? Cost of fencing = Rs (1200 x 75) / 100
= Rs. 900

Let breadth = b meters.
Then, length = 4b/3 meters.
? b x 4b/3 = 300

? b² = 300 x 3/4
? b² = 225
? b = 15

Hence, required difference = [(Length) - (Breadth) ]
= 4b/3 - b
= b/3
= 15/3 m
= 5 m

Let base = b and altitude = h
Then, Area = b x h

But New base = 110b / 100 = 11b / 10

Let New altitude = H
Then,
Decrese = (h - 10h /11 )
= h / 11


? Required decrease per cent
= (h/11) x (1 / h ) x 100 %

= 9¹/₁₁ %

Other side = ?5 ² - 4²
= ? 9
=3 m

So The area of the rectangular field = 4 x 3
= 12 m²

Area of the square = (84 + 84) m²
Area of the rectangle = (144 x width) m²

From question both area would be same,
? Width = (84 x 84) / 144 m = 49 m

Area of the plot = (3 x 1200) m²
= 3600 m²

Let breadth = y meters
Then Length = 4y meters,
Now area = 4y x y = 3600 m²
? y² = 900 m²
? y = 30 m

? Length of plot = 4y m
= (4 x 30) m
=120 m

Let the length, breadth and height of the room be l, b and h respectively

As per question
Cost of 2(l + b) x h = Rs. 48
? Required cost = cost of 2 (2l + 2b) x 2h
= cost of 4 [2(l + b) x h ]
= 4 x Rs. 48
= Rs. 192

Area of a four walls = 2(l + 8) x 6 = 168m²
? (l + 8) = 14
? l = 14-8
= 6 meters

Area of four walls = 2 x (l + b ) x h
? 2 x (7.5 + 3.5 ) x h = 77 m²
? h = 77 / (2 x 11) = 7/2
? h = 3.5 meters