Published by:
CGP EDU Academic Team
Published on: August 13, 2026
If 5, 5r, 5r 2 are the lengths of the sides of a triangle, then r cannot be equal to :
A
B
C
D
Text Solution
Verified by ExpertsThe correct answer is:
C
Sol. 5, 5r, 5r 2 sides of triangle,
5 + 5r > 5r 2 ….
5 + 5r 2 > 5r ….
5r + 5r 2 > 5 ….
from r 2 – r – 1 < 0,
…
from ,
r 2 – r + 1 > 0 ⇒ r ∈ R ….(5)
from ,
r 2 + r – 1 > 0
so, 
…(6)
from , (5), (6),
now check options
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