Answer:
the answer is 93°
Step-by-step explanation:
As you know that in a triangle,
angle1+angle2+angle3 = 180°
hence,
angle ABC + angle BAC + angle DCB + angle ACD ( Angle DCB + angle ACD = angle BCA) = 180°
75°+51°+2x+1x (let the ratio be x) = 180°
126°+3x = 180°
3x = 54°
x = 18°
2x = 36° = angle DCB
In triangle DCB,
51°+36°+angle BCD = 180°
angle BCD = 180°- 87°
Hence, angle BCD = 93°
