Steps of construction:
Step 1: Draw a line segment XY of 12cm.
Step 2: Draw ∠DXY = ∠B = 45o and ∠EYX = ∠C = 60o
Step 3: Draw the angle bisectors of angles of DXY and EYX which intersects each other at A.
Step 4: Draw the perpendicular of AX and AY which intersect XY at B and C respectively.
Step 5: Join AB and AC
Therefore Δ ABC is the required triangle