17 cm.

300 m, 900 m.

In the given parallelogram ABCD, DC = Base = 8 cm and AE = Height = 6cm
\(\therefore\) Area of the parallelogram = DC x AE = 8 X 6 cm² = 48 cm².

60 m²

Given, length = 5 m and breadth = 2.1 m
\(\therefore\) Area of a rectangle = Length x Breadth = 5 x 2.1 = 10.5 m²
Hence, area of rectangle is 10.5 m².

Given, circumference of the circular sheet = 154 m
\(\therefore\) Circumference of a circular sheet = 2\(\pi\)r
\(\Rightarrow \)         154 = 2\(\pi\)r
\(\Rightarrow \)             r = \(\frac{154}{2\pi}=\frac{154\times 7}{2\times 22}=\frac{7\times 7}{2}=\frac{49}{2}\)m
\(\therefore\)  Diameter = 2 x Radius
                   = 2 x \(\frac{49}{2}\)
                   = 49 cm.

Given, each side of the square = 3.5 cm
\(\therefore\) Area of the square = (Side)² = (3.5)² = 12.25 cm²
Now, perimeter of the square = 4 x Side
                                          = 4 x 3.5 = 14 cm.

Given, ABCD is a quadrilateral in which AC = 22 cm, BM = 3 cm, DN = 3 cm and BM \(\bot\) AC, DN \(\bot\) AC.
\(\therefore\)  Area of  \(\Delta\)ABC = \(\frac{1}{2}\times\) AC x BM          [\(\therefore\) Area of triangle = \(\frac{1}{2}\times\)Base x Height]
                            = \(\frac{1}{2}\times\)22 x 3 = \(\frac{66}{2}\) cm² = 33 cm²
and area of \(\Delta\)ABD = \(\frac{1}{2}\times\)AB x DN = \(\frac{1}{2}\times\)22 x 3
                            = \(\frac{66}{2}\) cm² = 33 cm²
Area of quadrilateral ABCD = Area of \(\Delta\)ABC + Area of \(\Delta\)ACD
                                       = 33 + 33 = 66 cm²
Hence, the area of quadrilateral ABCD is 66 cm².

Given, diameter of the circular garden = 21 m
\(\therefore\) Circumference of the circular garden = \(\pi d\)
                                                        = \(\frac{22}{7}\times 21\) = 66 m.
\(\therefore\) Length of the rope needed to make one round of fence
                       = Circumference of the circular garden = 66 m
\(\therefore\) Length of the rope needed to make two rounds of fence  = 2 x 66 = 132 m
Now, cost of 1 m rope = Rs 4
\(\therefore\) Cost of 132 m rope = Rs (4 x 132) =  Rs 528
Hence, the cost of the rope is Rs 528.

Given, length of a rectangular shape = 40 cm and breadth of a rectangular shape = 22 cm²
\(\therefore\) Length of wire = Perimeter of a rectangular shape
                        = 2 (l + b) = 2 (40 + 22) = 2 x 62 = 124 cm
Since, this wire is rebent in the shape of square.
\(\therefore\) Perimeter of the square = Length of wire  \(\Rightarrow\)   4 x Side = 124
On dividing both sides by 4, we get, Side = \(\frac{124}{4}=31cm\)
Hence, the side of a square shape is 31 cm.
\(\therefore\) Area of a rectangular shape = L x b = 40 x 22 = 880 cm² and area of square shape = (Side)² = (31)² = 961 cm²
Hence, area of square shape is more than the area of rectangular shape.

25 \(\pi\) cm²

\(\therefore\) Area of rectangle = I x b and area of circle = \(\pi\)r²
\(\therefore\) Area of total rectangular land = 15 m x 10 m
                                              =150 m²
Area of land covered by plants = 9 m x 1 m = 9 m²
Area of land covered by camel = 5 m x 3 m = 15 m²
Region of land covered by ox is circular area.
So, the diameter is given, d = 2.8 m
\(\therefore\)  Radius = \(\frac{d}{2}=\frac{2.8}{2}\) = 1.4 m.
\(\therefore\) Area of land covered by ox = \(\pi\)r²
                                           = \(\frac{22}{7}\) x 14 x 14 = 616 m²
Total area covered by plants, camel and ox
                   = 9 + 15 + 6.16 = 30.16 m²
Remaining land for living = Total area - Area covered by plants and animals
                                    = (150 - 30.16 ) m² = 119.84 m²
\(\therefore\) Ratio of areas kept for animals and plants to the living area
                      = 30.16: 119.84 = 3016: 11984 = 377: 1498
The value depicted here is that we should save our environment and balance environment.

Area of the squares MNOP= 144 cm² [given]
Since number of the triangles in square is 8.
So, area of each triangle will be \(\frac{144}{8}\) = 18 cm².

\(\therefore\) 1 km =1000 m
1 km² = 1000 x 1000= 1000000 m²
So, 1 km² is equal to 1000000 m².