Question

the equation cos⁻¹(3.4 / 10)=x can be used to determine the measure of angle bac. what is the degree measure of angle bac? round to the nearest whole degree.

Explanation:

Step1: Recall cosine - inverse formula

The cosine of an angle in a right - triangle is defined as $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$. Here, $\cos x=\frac{3.4}{10}$, so $x = \cos^{-1}(\frac{3.4}{10})$.

Step2: Calculate the angle

Using a calculator, $x=\cos^{-1}(0.34)$.
$x\approx70.12^{\circ}$.
Rounding to the nearest whole degree, $x\approx70^{\circ}$.

Answer:

$70^{\circ}$