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Question
If in a triangle, the angles are in A.P. and b: c = `sqrt3: sqrt2`, then A is equal to
Options
30°
60°
75°
45°
Solution
If in a triangle, the angles are in A.P. and b: c = `sqrt3: sqrt2`, then A is equal to 75°.
Explanation:
`angle"B"` = 60° `angle"A"` + `angle"C"` = 120
Now,
`b/c = sqrt3/sqrt2 = sin B/sin A`
sin C = `1/sqrt2`
`angle"C"` = 45°
Hence, `angle"A"` = 75°
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