Chapter 5 - Trigonometric Functions - Section 5.2 Trigonometric Functions: Unit Circle Approach - 5.2 Assess Your Understanding - Page 403: 94

$\dfrac{3}{2} =1.5$

We need to compute $\sec (\theta)$. We are given that $\cos \theta=\dfrac{2}{3}$ Since, $\sec (\theta) =\dfrac{1}{\cos (\theta)}$ Thus, we have: $\sec (\theta) =\dfrac{1}{\cos (\theta)} \\=\dfrac{1}{\frac{2}{3}} \\=\dfrac{3}{2} \\=1.5$