1. The problem asks to convert an angle from degrees to radians and express the answer as an exact fraction in terms of $\pi$. 2. The formula to convert degrees to radians is: $$\text{radians} = \text{degrees} \times \frac{\pi}{180}$$ 3. Applying the formula to 40°: $$40^\circ \times \frac{\pi}{180}$$ 4. Simplify the fraction $\frac{40}{180}$ by dividing numerator and denominator by their greatest common divisor, which is 20: $$40 \times \frac{\pi}{180} = \cancel{40}^{2} \times \frac{\pi}{\cancel{180}^{9}} = \frac{2\pi}{9}$$ 5. Therefore, the exact value of 40° in radians is: $$\boxed{\frac{2\pi}{9}}$$