Answer:
A. 37
Step-by-step explanation:
Given
The attached triangle and
[tex]c^2 = a^2 + b^2 -2abcos(C)[/tex]
Required
Find [tex]2abcos(C)[/tex]
From the attachment:
[tex]a = 4[/tex]
[tex]b = 5[/tex]
[tex]c = 2[/tex]
So, we have:
[tex]c^2 = a^2 + b^2 -2abcos(C)[/tex]
[tex]2^2=4^2 + 5^2 -2abcos(C)[/tex]
[tex]4=16 + 25 -2abcos(C)[/tex]
Collect like terms
[tex]2abcos(C)=16 + 25 -4[/tex]
[tex]2abcos(C)=37[/tex]
