Two sides of a triangle are of lengths 5 cm and 1.5 cm. The length of the third side of the triangle cannot be
(A) 3.6 cm
(B) 4.1 cm
(C) 3.8 cm
(D) 3.4 cm
[D]
Solution. We know that, sum of two sides of a triangle is greater than the third side.
(A) BC = 1.5 cm, AC = 3.6 cm (Assume)
Then, BC + AC = 1.5 + 3.6 cm = 5.1 cm
Sum of two side BC and AC is more than third side AB = 5 cm
Therefore, AC = 3.6 cm is possible.
(B) BC = 1.5 cm, AC = 4.1 cm (Assume)
Then, BC + AC = 1.5 + 4.1 cm = 5.6 cm
Sum of two side BC and AC is more than third side AB = 5 cm
Therefore, AC = 4.1 cm is possible.
(C) BC = 1.5 cm, AC = 3.8 cm (Assume)
Then, BC + AC = 1.5 + 3.8 cm = 5.3 cm
Sum of two side BC and AC is more than third side AB = 5 cm
Therefore, AC = 3.8 cm is possible.
(D) BC = 1.5 cm, AC = 3.4 cm (Assume)
Then, BC + AC = 1.5 + 3.4 cm = 4.9 cm
Sum of two side BC and AC is less than third side AB = 5 cm
Therefore, AC = 3.4 cm cannot be possible.
Hence option (D) is correct.