2.BD = CD + BC
CE = CD + DE
BE = BC + CD + DE
BD = AD - AB = BE - DE
3. Flat angle = 180,15 =112 flat angle.
Fillet = 360, 3/8 fillet = 360 * 3/8 = 135.
1 = 60', 25 15′=25.25
12.( 1)AB & gt； laser record
(2) AB = CD
(3)AB & lt； laser record
14. If BC is on the same side as A, AD = AB/2 = 8, AE = AC/2 = 20, DE = AE-AD = 20-8 = 12 cm.
If BC is on both sides of A, AD = AB/2 = 8, AE = AC/2 = 20, DE = AE+AD = 20+8 = 28 cm.
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