InterviewSolution
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Given `b = 2, c = sqrt3, angle A = 30^(@)`, then inradius of `DeltaABC` isA. `(sqrt3 -1)/(2)`B. `(sqrt3 + 1)/(2)`C. `(sqrt3-1)/(4)`D. none of these |
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Answer» Correct Answer - A `b = 2, c = sqrt3, anlge A = 30^(@)` `a = sqrt(b^(2) + c^(2) - 2bc cos A)` `= sqrt(4+3 - 2 xx 2 sqrt3 (sqrt3)/(2)) = 1` `rArr r = (s-a) tan.(A)/(2)` `= (b + c-a)/(2) tan.(A)/(2)` `= (sqrt3 +1)/(2) tan 15^(@)` `= (sqrt3 +1)/(2) (sqrt3 -1)/(sqrt3+1) = (sqrt3 -1)/(2)` |
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