MathDB

15

Part of 2001 Stanford Mathematics Tournament

Problems(1)

2001 Stanford Math Tournament Team #15

Source:

5/24/2014
Let ABCABC be an isosceles triangle with ∠ABC=∠ACB=80∘\angle{ABC} = \angle{ACB} = 80^\circ. Let DD be a point on ABAB such that ∠DCB=60∘\angle{DCB} = 60^\circ and EE be a point on ACAC such that ∠ABE=30∘\angle{ABE} = 30^\circ. Find ∠CDE\angle{CDE} in degrees.
Stanfordcollegetrigonometrygeometrytrig identitiesLaw of Sines