Question

In a triangle LMN, <L=81°, n=4.3cm and m=3.5cm. Calculate:

1. Length l
2. Angles M and N

Answer 1

1. 
   
   L² = 4.3² + 3.5² – 2 x 4.3 x 3.5Cos 81°         
   L = 5.10 cm
2.    5.1   =    4.3  
   Sin 81     Sin N
   Sin N = 4.3Sin81
                    5.1
   Sin N = 0.8328               M2
   N = 56.38°
   M = 180 – (81+56.38) = 42.62°