Circumference-3.5dm. What is the length of the second circle, whose diameter is 5/7 of the diameter of the first circle?

To solve this problem, recall the formula for calculating the circumference through the diameter: C = πd, where C is the circumference, d is the diameter of the circle. Let’s calculate what the diameter is, knowing that the circumference is 3.5 dm.

3.14 * d = 3.5;

d = 3.5 / 3.14;

d = 1.11.

Let’s calculate what the diameter of the second circle is. To find a part of a number, you need to multiply this number by a part.

1.11 * 5/7 = 5.55 / 7 = 0.79.

Let’s calculate the length of the second circle.

C = 3.14 * 0.79 = 2.4806 dm.

Answer: 2.4806 decimeters.