What can replace k in the following equation?
\(\sqrt{86.49}+\sqrt{5+k^2}=12.3\)
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
The first square root is a perfect square of a decimal, so the second root is found by subtraction and then squared.
\(\sqrt{86.49}=9.3\), since \(93^2=8649\)
\(\sqrt{5+k^2}=12.3-9.3=3\)
\(5+k^2=9\), so \(k^2=4\) and \(k=2\) (or \(-2\), not among the options)