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A triangle is to be constructed with perimeter P cm and base angles 50° and 70°. Two students choose P = 5 cm and P = 15 cm.
Which statement about their two finished triangles is correct?

Class 9Constructions of TrianglesGeometry
  • ASame shape (similar) but different sizes
  • BCongruent triangles
  • CDifferent shapes
  • DOnly the P = 15 cm one is valid

Step-by-Step Solution

Both triangles have the same three angles (50, 70, 60°), so they are similar in shape. Different perimeters make them different sizes, hence similar but not congruent.
Answer: A) Same shape (similar) but different sizes

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