How many measurements are needed to construct a quadrilateral uniquely?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Five
A diagonal splits a quadrilateral into two triangles, and a triangle is fixed by three measurements. The two triangles share the diagonal, so \(3+3-1=5\) measurements fix the quadrilateral, for example four sides and one diagonal.
Four measurements are not enough: a square of side 4 cm can be pushed into a rhombus with the same four sides, so the four sides alone do not fix the shape.