Question

What is the value of cos0 ?

Answer 1

Answer:

$\frac{9}{10}$

Step-by-step explanation:

The Law of Cosines works for any triangle and is given by:

$c^2=a^2+b^2-2ab\cos \gamma$, where $a$, $b$, and $c$ are the sides of the triangle and $\gamma$ is the angle opposite to $c$.

In the given triangle, assign the variables:

• $c\implies 10$
• $a\implies 10$
• $b\implies 18$

Substituting these variables, we have:

$10^2=10^2+18^2-2(10)(18)\cod \cos \gamma,\\100=100+324-360\cdot \cos \gamma,\\100=424-360\cos \gamma,\\-324=-360\cos\gamma,\\\cos \gamma =\frac{-324}{-360}=\boxed{\frac{9}{10}}$