As shown in the figure, in △ ABC, ab = AC, points D and E are two points on the edge of BC, and ad = BD, AE = CE. If ∠ DAE = 60 °, calculate the degree of ∠ BAC

As shown in the figure, in △ ABC, ab = AC, points D and E are two points on the edge of BC, and ad = BD, AE = CE. If ∠ DAE = 60 °, calculate the degree of ∠ BAC

From ad = BD, we know ∠ B = ∠ bad, AE = CE, we know ∠ C = ∠ EAC
∠BAC=∠BAD+∠EAC+∠DAE=∠B+∠C+60
And ∠ BAC + ∠ B + ∠ C = 180, that is ∠ B + ∠ C + 60 + ∠ B + ∠ C = 180
Therefore, B + C = 60
Then ∠ BAC = 60 + 60 = 120