Use the sine rule for triangles:
All three angles of a triangle = 180°
So angle L = 180 - 60 - 45 = 75 degrees
sin(60)/12 = sin(75)/KM
KM = (sin(75) x 12)/sin(60)
KM = 13.38 unit
s
sin(60)/12 = sin(45)/KL
KL = (sin(45)x12)/sin(60)
KL = 9.8 units
Perimeter = LM + KM + KL
Perimeter = 12 + 13.38 + 9.8
Perimeter = 35.18 units
