Question

find the angle of the triangle formed by a) (-2, 3), (3, 8), (4, 1)

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Answer 1

We know that angle between two points is

cosA=[a1a2+b1b1/√(a²1+b²1)√(a²2+b²2)]

given A=(-2,3)

B=(3,8)

[-2*3+8*3/(√-2²+3²)(√3²+8²)]

[-6+24/√14*√73]

18/√14*√73