24. Using the law of cosine, which of the following should be used to find the measure of side $c$ ?
A. $c^{2}=a^{2}+b^{2}-2 a b(\cos C)$
C. $c^{2}=a^{2}+b^{2}-2 a b(\cos A)$
B. $c^{2}=a^{2}+b^{2}-2 b c(\cos B)$
D. $c^{2}=a^{2}+b^{2}-2 b c(\cos C)$

Answer

Expert–verified

Hide Steps

Answer

The final answer is: $\boxed{c^{2} = a^{2} + b^{2} - 2ab(\cos C)}$

Steps

Step 1 ：Use the law of cosine to find the measure of side c: $c^{2} = a^{2} + b^{2} - 2ab(\cos C)$

Step 2 ：The final answer is: $\boxed{c^{2} = a^{2} + b^{2} - 2ab(\cos C)}$