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The lengths of the sides of a right angled triangle are (3x + 1)cm, (3x - 1)cm and xcm. ...

The lengths of the sides of a right angled triangle are (3x + 1)cm, (3x - 1)cm and xcm. Find x
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A 2
  • B 6
  • C 18
  • D 12
  • E 5
Correct Answer: Option D
Explanation:
\((3x + 1)^{2} = (3x - 1)^{2} + x^{2}\)Â (Pythagoras's theorem)
\(9x^{2} + 6x + 1 = 9x^{2} - 6x + 1 + x^{2}\)
x2 - 12x = 0
x(x - 12) = 0
x = 0 or 12
The sides cannot be 0 hence x = 12.

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