SSC JE Civil Engineering 29-Oct-2020 Shift 1 Paper

Here object is a “rectangle”
Area of rectangle on MAP $=1.5\times .5=0.75{\mathrm{cm}}^2$
Area of rectangle on ground $=12{\mathrm{km}}^2$ (given)
Area scale $=\frac{\left(0.75\times {10}^{-4}\right){\mathrm{m}}^2}{\left(12\times {10}^6\right){\mathrm{m}}^2}=\left(\frac{1}{16\times {10}^{10}}\right)$
This is not given, so we calculate, length scale
(length scale) $=$ (width scale)
$\frac{\mathrm{L}}{1.5}=\frac{\mathrm{B}}{0.5}$ [L, B are length and breadth of rectangle an ground]
$\Rightarrow \mathrm{L}=3\mathrm{D}$
Further given that $\mathrm{L}\times \mathrm{B}=12$
$3\mathrm{B}\times \mathrm{B}=12\Rightarrow \mathrm{B}=2\mathrm{km}$ and $\mathrm{L}=6\mathrm{km}$
Now, linear length scale $=\left(\frac{1.5\times {10}^{-2}}{6\times {10}^3}\right)=\frac{1}{40,0000}$