Answer:
80
Good luck :)
Step-by-step explanation:
[tex]\sqrt{a} * \sqrt{b} = \sqrt{ab}[/tex]
[tex]\sqrt{6400}[/tex]
6400 = 2 * 2 * 2 * 2 * 2 * 2 * 2 *2 * 5 * 5
= 2^8 * 5^2
2^4 * 5
16*5 = 80