Answer:
√126
Option D is the right option.
solution,
[tex] \frac{ac}{bc} = \frac{bc}{dc} \\ or \: \frac{18}{ m} = \frac{m}{7} \\ or \: m \times \: m = 18 \times 7(cross \: multiplication) \\ or \: {m}^{2} = 126 \\ m = \sqrt{126} [/tex]
Hope this helps..
Good luck on your assignment.
Hope
