1. **State the problem:** We are given a triangle with sides 8 units and 7 units enclosing an angle $\theta$. The area of the triangle is $14\sqrt{3}$ square units. We need to find $\cos \theta$ as a fraction.
2. **Formula for the area of a triangle using two sides and the included angle:**
$$\text{Area} = \frac{1}{2}ab\sin \theta$$
where $a=8$, $b=7$, and the area is $14\sqrt{3}$.
3. **Substitute the known values:**
$$14\sqrt{3} = \frac{1}{2} \times 8 \times 7 \times \sin \theta$$
4. **Simplify the right side:**
$$14\sqrt{3} = 28 \sin \theta$$
5. **Solve for $\sin \theta$:**
$$\sin \theta = \frac{14\sqrt{3}}{28} = \frac{\sqrt{3}}{2}$$
6. **Recall the Pythagorean identity:**
$$\sin^2 \theta + \cos^2 \theta = 1$$
7. **Substitute $\sin \theta = \frac{\sqrt{3}}{2}$:**
$$\left(\frac{\sqrt{3}}{2}\right)^2 + \cos^2 \theta = 1$$
$$\frac{3}{4} + \cos^2 \theta = 1$$
8. **Solve for $\cos^2 \theta$:**
$$\cos^2 \theta = 1 - \frac{3}{4} = \frac{1}{4}$$
9. **Take the square root:**
$$\cos \theta = \pm \frac{1}{2}$$
10. **Determine the correct sign:** Since $\sin \theta = \frac{\sqrt{3}}{2}$ corresponds to $\theta = 60^\circ$ or $120^\circ$, and the triangle sides suggest an acute angle, we take the positive value.
**Final answer:**
$$\cos \theta = \frac{1}{2}$$
Cos Theta Ffce9B
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