How is root245 7root5, how do you work it out?

Question

isnt 5*43 245 and you cant simplify that further?

Answer 1

you mean how did this happen:
sqrt(245) = 7*sqrt(5)
if so,
first you factor out 245:
245 = 5 * 49 = 5 * 7 * 7 = 5 * 7^2
therefore,
sqrt(5 * 7^2)
we can also rewrite this as
sqrt(5) * sqrt(7^2)
we can take out the seven since the sqrt(7^2) is equal to 7, and leave the 5 inside:
7*sqrt(5)

hope this helps~ :)