Find the height of this triangle.

x^2 = 4^2 - 2^2

x^2 = 16 - 4

x^2 = 12

x = √12

x = 2√3

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)