Question

B E 13. In each of the following figures, one side of a triangle has been produced. Find all the angles of the triangle in each case.
$exterior \: angle \: = \: sum \: of \: interior \: opposite \: angle$
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Answer 1

Question - iv)

➟ ∠ABC = 180° - ∠EBC⠀⠀(∠s on a straight line)

➟ y° = 180° - 140°

➟ y° = 40°

➟ ∠ACB = 180° - ∠ACD⠀⠀(∠s on a straight line)

➟ z° = 180° - 130°

➟ z° = 50°

➟ x° + y° + z° = 180°⠀⠀(Sum of ∠s of a ∆)

➟ x° + 40° + 50° = 180°

➟ x° + 90° = 180°

➟ x° = 180° - 90°

➟ x° = 90°

Question - vi)

➟ ∠ABC = 180° - ∠DBC⠀⠀(∠s on a straight line)

➟ ∠ABC = 180° - 130°

➟ ∠ABC = 50°

➟ ∠ABC + ∠BAC + ∠ACB = 180°⠀⠀(Sum of ∠s of a ∆)

➟ 50° + x° + x° = 180°

➟ 2x° = 180° - 50°

➟ 2x° = 130°

➟ x° = 130/2

➟ x° = 65°

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