1) 45°
2) 45°
3) BC= 3 AB= sqrt(18)=3sqrt(2)
4) BC= 4 AB= sqrt(32)=4sqrt(2)
5) 9sqrt(2)
6) 7
7) 2
sqrt means square root
AC = AB because it is isosceles
pythagore theorem is used to solve 3 to 7
AB²= AC²+CB²
In 1 and 2 it is the angle in an isosceles triangle