Question

If two sides of a triangle are 5 cm and 1.5 cm, the lenght of its third side cannot be . . . . . . . . Choose the correct alternative answer for the question.
(A) 3.7 cm
(B) 4.1 cm
(C) 3.8 cm
(D) 3.4 cm

Answer 1

(D) 3.4 cm
The sum of any two sides of triangle is always greater than third side.(triangle inequality theorem)
3.4+1.5<5
4.9<5

Answer 2

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The difference of any two sides

is less than the third side .

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Here ,

Let a , b and c are three sides

of a triangle.

a = 5 cm , b = 1.5 cm

third side > a - b

c > 5 - 1.5

c > 3.5

But ,

3,4 > 3.5 ( False )

Therefore ,

Third side cannot be 3.4 .

Option ( D ) is correct.

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