Given the equation [tex]\( -1\left(\frac{3.4}{10}\right) = x \)[/tex], determine the degree measure of angle BAC. Round to the nearest whole degree.

A. [tex]\( 19^{\circ} \)[/tex]
B. [tex]\( 20^{\circ} \)[/tex]
C. [tex]\( 70^{\circ} \)[/tex]
D. [tex]\( 71^{\circ} \)[/tex]



Answer :

First, let's solve for [tex]\( x \)[/tex]:
[tex]\[ x = -\left(\frac{3.4}{10}\right) \][/tex]

Simplify the fraction:
[tex]\[ \frac{3.4}{10} = 0.34 \][/tex]

Apply the negative sign:
[tex]\[ x = -0.34 \][/tex]

Next, we need to determine the angle [tex]\( \angle BAC \)[/tex] whose cosine is [tex]\( -0.34 \)[/tex]. This involves using the inverse cosine (arccos) function:
[tex]\[ \angle BAC = \arccos(-0.34) \][/tex]

When we evaluate the inverse cosine of [tex]\( -0.34 \)[/tex], we find that:
[tex]\[ \arccos(-0.34) \approx 1.9177 \text{ radians} \][/tex]

To convert the value from radians to degrees, we use the conversion factor [tex]\( \frac{180}{\pi} \)[/tex]:
[tex]\[ \angle BAC = 1.9177 \times \frac{180}{\pi} \][/tex]

Approximating [tex]\( \pi \)[/tex] to 3.14159, we get:
[tex]\[ \angle BAC \approx 1.9177 \times 57.2958 \][/tex]

When we multiply these values together:
[tex]\[ \angle BAC \approx 109.8769^\circ \][/tex]

Finally, we round [tex]\( 109.8769^\circ \)[/tex] to the nearest whole degree:
[tex]\[ \angle BAC \approx 110^\circ \][/tex]

Thus, the degree measure of [tex]\( \angle BAC \)[/tex] is [tex]\( 110 \)[/tex] degrees. Given the provided answer choices, the angle [tex]\( \angle BAC \)[/tex] rounded to the nearest whole degree is:
[tex]\[ 70^{\circ} = false \][/tex]
[tex]\[ 71^{\circ} = false \][/tex]
[tex]\[ 19^{\circ} = false \][/tex]
[tex]\[ 20^{\circ} = false \][/tex]
But correct rounded answer is [tex]\(110 \text{ degrees} \)[/tex], but none of provided options matches the correct right one.

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