1. **State the problem:** We need to determine if a 50 cm ribbon is long enough to go all the way around the cake. 2. **Understanding the shape:** The top of the cake is a circle with a diameter of 7 inches. 3. **Calculate the circumference of the circle:** The formula for circumference $C$ is given by $$C = \pi \times \text{diameter}$$ So, $$C = \pi \times 7 = 7\pi \text{ inches}$$ 4. **Convert the circumference from inches to centimeters:** Given 1 inch = 2.54 cm, we have $$C = 7\pi \times 2.54 = 7 \times 3.1416 \times 2.54 \approx 55.88 \text{ cm}$$ 5. **Compare ribbon length and circumference:** The ribbon length is 50 cm, but the circle's circumference is approximately 55.88 cm. 6. **Conclusion:** Since 50 cm < 55.88 cm, one length of ribbon is **not** long enough to go all the way around the cake.