The law of cosines states for a triangle ABC with side lengths a, b, and c.
Check the final answer first, then review the worked steps.
Check the final answer first, then review the worked steps.
3. Match the Formula to the Options: We need to find the option that correctly states the Law of Cosines. The image shows a triangle ABC with sides labeled $a$, $b$, and $c$ opposite to vertices A, B, and C respectively. The question is asking for the law of cosines statement. Let's examine the given options:
A. $c^2 = a^2 - b^2 - 2bccos(C)$ - This is incorrect because it has a minus sign before $b^2$ and uses $bc$ instead of $ab$ with $\cos(C)$.
B. $c^2 = a^2 + b^2 - 2abcos(C)$ - This matches the standard form of the Law of Cosines when solving for side $c$ using angle $C$.
C. $c^2 = a^2 + b^2 - 2bc cos(B)$ - This is incorrect because it uses $\cos(B)$ instead of $\cos(C)$ and the product of sides $bc$ instead of $ab$.
D. $c^2 = a^2 + b^2 - 2bc cos(A)$ - This is incorrect because it uses $\cos(A)$ instead of $\cos(C)$ and the product of sides $bc$ instead of $ab$.