$\"\"$

The trigonometric function $\"\"$ .

$\"\"$ (Original function)

$\"\"$ (Apply inverse cos function each side) \ \

$\"\"$ (Substitute: $\"\"$ )

$\"\"$ (Use calculator) \ \ Therefore, the angle of $\"\"$ is nearest degree is $\"\"$ . $\"\"$

Rounded to the nearest degree, $\"\"$ .