(b) Evaluate \( \frac{4.5\left(\cos 30^{\circ}\right)}{\sqrt{3}}-2 \)

To evaluate \( \frac{4.5\left(\cos 30^{\circ}\right)}{\sqrt{3}}-2 \), we start by finding \( \cos 30^{\circ} \), which is \( \frac{\sqrt{3}}{2} \). Now substituting this value into the equation: \[ \frac{4.5\left(\frac{\sqrt{3}}{2}\right)}{\sqrt{3}} - 2 \] This simplifies to: \[ \frac{4.5\sqrt{3}/2}{\sqrt{3}} - 2 \] The \( \sqrt{3} \) in the numerator and denominator cancels out, leaving us with: \[ \frac{4.5}{2} - 2 \] Calculating \( \frac{4.5}{2} \) yields \( 2.25 \): \[ 2.25 - 2 \] Finally, \( 2.25 - 2 = 0.25 \). So, the evaluated expression is \( 0.25 \).