Question

    Given are three points A(2, 7), B(4,

    -1), C(- 2, 6) on a plane. What kind of triangle is formed by joining the points A, B, and C?
    A Right Triangle Correct Answer Incorrect Answer
    B Equilateral Triangle Correct Answer Incorrect Answer
    C Isosceles Triangle Correct Answer Incorrect Answer
    D Obtuse Triangle Correct Answer Incorrect Answer

    Solution

    A(2, 7), B(4, -1), C(-2, 6) AB = (4 + 64) = 68 BC = (36 + 49) = 85 AC = (16+1) = 17 We see that AB² + AC² = BC² (follows Pythagoras theorem) The triangle is a right triangle at A(2, 7).

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