Question

The longest side of an obtuse triangle measures 20 cm. The two shorter sides measure x cm and 3x cm

Answer 1

Obtuse triangle is a triangle that has an angle that is greater than 90°.

longest side: 20 cm
two shorter sides: x cm and 3x cm

choice given: 6.3   6.4   7.0   7.1

Obtuse triangle Pythagorean Theorem

c² > a² + b²

20² > x² + 3x²
400 > 4x²
÷4      ÷4
 100 > x²
   10 > x
  
400 > 4(7.1)²
400 > 4(50.41)
400 > 201.64

The greatest possible value of x is 7.10