In AABD = 62-(-3)? (Pythagorean Theorem)
In ABCD 2 - 02-12
(Pythagorean Theorem)
c2 - 82 +261 - 12 = 22 - 92
(on simplification)
c2 - (62 – 265 + 32) = 22 - 32
(on simplification)
c2 -(6-1)² = 92 – 12
(Transitive Property)
Draw a perpendicular, BD, from B to side
AC.
Let DC = 1 and BD = k
Therefore, AD =b-.
Therefore, c? = 22 +62 - 2abcosc