So in the first triangle with the 3 in it. You have root 3 and use the a^2 +b^2=c^2 formula. So 3^2 + 3^2= x^2 and then when you solve you get radical 18^2 which is equal to radical 18 or square root 18. Then we go to the bigger triangle and we do the same formula but this time we have the c value which is 9. So we do radical 18^2 + x^2 = 9^2 and then solve that and minus 18 from the 81 since the radical goes off the 18 and you get square root63.
Sorry i couldn't use the signs. Sorry If I'm wrong Hope this helps!.
