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प्रश्न
In the following figure, shows the cross-section of railway tunnel. The radius OA of the circular part is 2 m. If ∠AOB = 90°, calculate:
the area of the cross-section.
उत्तर
We have a cross section of a railway tunnel. `ΔOAB`is a right angled isosceles triangle, right angled at O. let OM be perpendicular to AB.
Area of cross section,
`3/4 ("Area of circle")+"Area o"f ΔOAB`
`=(pi)(2)^2(3/4)+1/2(2)(2)`
`=(3pi+2)m^2`
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