In ΔKLM, l = 3.7 cm, m = 5.2 cm and ∠K=124°. Find the length of k, to the nearest 10th of a centimeter.

7.9

Step-by-step explanation:

k^2 = 3.7^2+5.2^2-2(3.7)(5.2)\cos 124

k  

2

=3.7  

2

+5.2  

2

−2(3.7)(5.2)cos124

Plug in values.

k^2 = 13.69+27.04-2(3.7)(5.2)(-0.559193)

k  

2

=13.69+27.04−2(3.7)(5.2)(−0.559193)

Square and find cosine.

k^2 = 13.69+27.04+21.51774

k  

2

=13.69+27.04+21.51774

Multiply.

k^2 = 62.24774

k  

2

=62.24774

Add.

k=\sqrt{62.24774} \approx7.89 \approx7.9

k=  

62.24774

​  

≈7.89≈7.9