Explanation:
12cm, 5cm, 13cm
In (a)
12\(^{1}\) + 5\(^{1}\) = 13\(^{1}\)
144 + 25 = 169
169
Since, the sum of the square of two smallest side is equal to the square of largest side.
Hence, a right triangle can be constructed.
In (b)
8\(^{1}\) + 6\(^{1}\) = 10\(^{1}\)
44 + 36 = 100
100 = 100
Since, the sum of the square of two smallest side is equal to the square of largest side.
Hence, a right triangle can be constructed.
In (c)
\(5^2+9^2\neq11^2\)
\(\Rightarrow 25+81\neq121\)
\(\Rightarrow 106\neq121\)
Since, the sum of the square of two smallest side is not equal to the square of largest side.
Hence, a right triangle can not be constructed.
Hence, the correct answer is option (c).