UPSC CDS 1 2022 Math Paper

Given:
Distance from the point of observation =10km
The aeroplane is at a height of 8km above the ground
Concept used:
sin‌θ=P∕H
Here P= Perpendicular, H= Hypotenuse According to the question,
AC=10km
So, sin‌θ=AB∕AC
⇒sin‌θ=8∕10=4∕5=0.8
Since,
sin‌45∘=1∕√‌2≈0.71
sin‌60∘=√‌3∕2≈0.87
‌ As, ‌0.71≤sin‌θ≤0.87
⇒45∘≤θ≤60∘
∴ Required answer is 45∘<θ<60∘