We will solve this task in steps and explain each of them in detail.
1) 11 * 2 = 22 centimeters – the length of the base of an isosceles triangle, since the middle line parallel to the base is 11 centimeters;
2) 64 – 22 = 42 centimeters – the sum of the lengths of the sides, since the perimeter of an isosceles triangle is 64 centimeters, and the length of the base is 22 centimeters;
3) 42: 2 = 21 centimeters – the length of the side, since the sum of the sides is 42 centimeters, and they are equal to each other.
Answer: 21 centimeters.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.