ΔACB ΔCDA
AC² + BC² = AB² AD² + CD² = AC²
BC² = AB² - AC² BC² + CD² = AC² (AD=BC is given)
BC² = AC² - CD²
AB² - AC² = AC² - CD² (both sides were = to BC²)
AB² + CD² = 2AC²
(3)² + (√2)² = 2AC² (AB=3 and CD=√2 were given)
9 + 2 = 2AC²
11 = 2AC²
[tex]\frac{11}{2}[/tex] = AC²
[tex]\sqrt{\frac{11}{2} }[/tex] = AC
[tex]\frac{11\sqrt{2} }{2}[/tex] = AC
