Answer:
the bicycle travels approximately 6.15 km if the wheel makes 391 complete turns.
Explanation:
Each time the wheel makes one complete turn, it travels a distance equal to the circumference of the wheel. The circumference of a circle can be calculated using the formula:
C = 2πr
where C is the circumference, π (pi) is a mathematical constant approximately equal to 3.14, and r is the radius.
In this case, the radius of the bicycle wheel is 25 cm, so its circumference is:
C = 2πr = 2π(25 cm) = 50π cm
To find the distance travelled by the bicycle in kilometers, we need to convert the circumference from centimeters to kilometers and then multiply it by the number of complete turns:
distance = (number of turns) x (circumference) / 100,000
where 100,000 is the number of centimeters in a kilometer.
Plugging in the numbers, we get:
distance = (391 turns) x (50π cm) / 100,000 = 391π / 200 km
Using a calculator or approximating π as 3.14, we get:
distance ≈ 6.15 km
Therefore, the bicycle travels approximately 6.15 km if the wheel makes 391 complete turns.