As shown in the figure, we can know that AC=AC'+C'D+CD, C'D=CD=(5-AC')/2= 1 from symmetry, so there is AD=4, so we can know BD=3 from Pythagorean theorem, and BC= root sign (BD * BD+CD *) from Pythagorean theorem. And 2 10 refers to the case of C' on the CA extension line. Similarly, you can try to find it yourself!