In the figure, if LK = 6√3 , MK = 12, find the remaining sides of □LMNK and also perimeter of □ LMNK.

In the figure, if LK = 6√3 , MK = 12, find the remaining sides of □LMNK and also perimeter of □ LMNK. 

Solution:
In ∆ MLK, m∠ L = 900 , m∠ K = 300
∴ m∠ M = 600 [Remaining angle of a triangle]
∴ ∆ MLK, is a 300 – 600 – 900 triangle
Now, Side opposite to 300 =  1/2 [Hyp]
∴ ML = ½ [MK]
∴ ML = ½ [12]
∴ ML = 6 cm

Now, in ∆ MNK, ∠ N = 450 , ∠ K = 900 [Given]
∴ ∠ M = 450 [Remaining angle of a triangle]
∴ MNK, is a 450 , 45‑0, 900  triangle
∴ side opposite to 450 = 1/√2 [Hyp]
∴ MK = KN = 1/√2 [MN]
∴ 12 = KN = 1/√2 [MN]
∴ KN = 12
&
12 = 1/√2  [MN]

&
12√2  = MN



P(□ LMNK) = LM + MN + NK + LK
∴ P(□ LMNK) = 6 + 12√2 +12 + 6√3   
∴ P(□ LMNK) = 18 +  12√2 + 6√3    
∴ P(□ LMNK) = 6(3 + 2√2 +√3) cm