1. The problem asks to find the circumference of a circle with a diameter of 158 cm, rounded to 1 decimal place. 2. The formula for the circumference $C$ of a circle is: $$C = \pi d$$ where $d$ is the diameter. 3. Substitute the given diameter $d = 158$ cm into the formula: $$C = \pi \times 158$$ 4. Using $\pi \approx 3.1416$, calculate: $$C \approx 3.1416 \times 158 = 496.371$$ 5. Round the result to 1 decimal place: $$C \approx 496.4 \text{ cm}$$ So, the circumference of the circle is approximately 496.4 cm.