CBSE Class 4 Mathematics: Unit 13 Fields and Fences NCERT Solutions

To find the length of the boundary of the field, we need to add the lengths of all its sides. This is also known as calculating the perimeter.

The lengths of the sides are given as 9 metre, 15 metre, 21 metre, and 9 metre.

Length of the boundary = Sum of the lengths of all sides

= 9 m + 15 m + 21 m + 9 m

= 54 metre

Therefore, the length of the boundary of Rahmat's field is 54 metres.

First, we need to know how much wire Rahmat used for his field's boundary. From the previous question, we know Rahmat used 54 metres of wire.

The total length of wire Rahmat had initially was 70 metres.

To find out how much wire was left, we subtract the wire used from the total wire Rahmat had:

Wire left = Total wire - Wire used for boundary

$$Wire\; left\; =\; 70\; \backslash text\{\; m\}\; -\; 54\; \backslash text\{\; m\}\; =\; 16\; \backslash text\{\; m\}$$

So, Rahmat gave 16 metres of wire to Ganpat.

1. To find the length of the boundary of Ganpat's field, we add the lengths of all its sides:

   The sides are 9m, 15m, 15m, 9m, and 18m.

   Length of Ganpat's boundary = 9 m + 15 m + 15 m + 9 m + 18 m

   $$Length\; of\; Ganpat\text{'}s\; boundary\; =\; 66\; \backslash text\{\; m\}$$

   So, the boundary of Ganpat's field is 66 metres long.

2. Ganpat needs a total of 66 metres of wire for his field. Rahmat gave him 16 metres of wire. To find out how much more wire Ganpat needs, we subtract the wire he received from the total length required.

   More wire needed = Total boundary length - Wire received from Rahmat

   $$More\; wire\; needed\; =\; 66\; \backslash text\{\; m\}\; -\; 16\; \backslash text\{\; m\}\; =\; 50\; \backslash text\{\; m\}$$

   Therefore, Ganpat needs 50 metres more wire to fence his field.

We need to calculate the perimeter (boundary length) for each field by adding the lengths of all its sides.

1. Boundary of Field (a):

   Sides are 15 m, 6 m, 15 m, 24 m.

   Boundary = 15 m + 6 m + 15 m + 24 m = 60 metre.

2. Boundary of Field (b):

   Sides are 9 m, 6 m, 3 m, 6 m, 6 m, 12 m.

   Boundary = 9 m + 6 m + 3 m + 6 m + 6 m + 12 m = 42 metre.

3. Boundary of Field (c):

   Sides are 9 m, 12 m, 15 m.

   Boundary = 9 m + 12 m + 15 m = 36 metre.

4. Boundary of Field (d):

   Sides are 15 m, 15 m, 9 m, 15 m, 15 m, 9 m.

   Boundary = 15 m + 15 m + 9 m + 15 m + 15 m + 9 m = 78 metre.

5. Comparing the boundary lengths:
   • Field (a): 60 metre
   • Field (b): 42 metre
   • Field (c): 36 metre
   • Field (d): 78 metre

   The longest boundary is 78 metres, which belongs to Field (d).

   Therefore, field (d) has the longest boundary.

The problem states that Chandu's father takes four rounds of Chandu's field every morning. One round around the field is equal to the perimeter (boundary length) of the field.

To find the total distance he covers, we need to multiply the length of one round (the perimeter of the field) by the number of rounds he takes.

Total distance = 4 × (Perimeter of Chandu's field)

Since the dimensions of Chandu's field are not provided in the given text, we cannot calculate a specific numerical answer for the distance covered. However, if the perimeter of Chandu's field were known, say 'P' metres, then the total distance covered would be 4 × P metres.