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In the diagram, △XYZ is produced to T. if |XY| = |ZY| and ∠XYT = 40°, find ∠XZT

  • A 110°
  • B 130°
  • C 140°
  • D 180°
waec 2021mathematics

The correct answer is A. 110°

Isosceles Triangle. Two equal sides. Two equal angles ;

∠ X = âˆ  Z

∠Y + âˆ X + Z = 180  --> 40° + âˆ X + âˆ X = 180°

∠2X = 180° - 40° = 140°

∠X = 70°, i.e âˆ X = 70 and âˆ Z = 70°.

The exterior angle of triangle is the sum of two opposite internal angles

: âˆ X + ∠Y = âˆ XZT

=70° + 40° = 110°

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