a triangle with two identical angles and one different angle is an isoceles triangle; the two sides across from the identical anlges are the exact same
pythagoren theorem
AB² = AC² + BC²
since this is isoceles and AC is the same as BC, we can let BC = AC and so
AB² = AC² + AC²
AB² = 2AC²
AC² = AB² / 2
AC = √(AB² / 2)
AC = √( (19√2)² / 2)
AC = √( (19² ·2 ) / 2)
AC = √361
AC = 19 m
and isosceles so BC = 19 m