√(86.49)+ √(5+k^2)=12.3. So k is equal to (a)√10 (b) 2√5 (c) 3√5 (d) 2

Question

\(\sqrt{86.49}\) + \(\sqrt{5+K^2}\) = 12.3. So k is equal to

(a) \(\sqrt{10}\)

(b) \(2\sqrt5\)

(c) \(3\sqrt5\)

(d) 2

Answer 1

(d) 2

\(\sqrt{86.49} + \sqrt{5+k^2}\) = 12.3

\(\Rightarrow\) \(\sqrt{5+k^2}\) =12.3 - \(\sqrt{86.49}\) = 12.3- 9.3 = 3

\(\Rightarrow\) 5 + k²= 9 (on squaring both the sides)

\(\Rightarrow\) k²= 9 - 5 = 4 \(\Rightarrow\) k = 2