The diameter of a circle is a straight line that passes through the center of the circle and touches two points on the circle. It is the longest distance you can measure across a circle. The diameter is a fundamental property of a circle and is used to calculate other important measurements such as the circumference and area of a circle.

- The diameter is the distance across a circle through its center.
- The diameter is twice the length of the radius of a circle. In other words, diameter = 2 * radius.
- The formula to calculate the diameter of a circle is: diameter = 2 * radius.
- The diameter is used to calculate the circumference and area of a circle.
- The diameter can be used to divide a circle into two equal halves, known as semicircles.

- What is the definition of the diameter of a circle?
- How is the diameter related to the radius of a circle?
- What is the formula to calculate the diameter of a circle?
- How is the diameter used to calculate the circumference of a circle?
- How is the diameter used to calculate the area of a circle?

Study GuideCells- The building blocks of living things Activity LessonCells - Building Blocks of Living Things Worksheet/Answer key

Cells- The building blocks of living things Worksheet/Answer key

Cells- The building blocks of living things Worksheet/Answer key

Cells- The building blocks of living things Worksheet/Answer keyCells - The Building Blocks of Living Things Worksheet/Answer keyFocus In Vocabulary/Answer key

Cells- The building blocks of living things Vocabulary/Answer key

Cells- The building blocks of living things Vocabulary/Answer key

Cells- The building blocks of living things

The Living Environment: Students understand that cells are the basic unit of life, that all life as we know it has evolved through genetic transfer and natural selection to create a great diversity of organisms, and that these organisms create interdependent webs through which matter and energy flow. Students understand similarities and differences between humans and other organisms and the interconnections of these interdependent webs.

Cells: Students describe how living things are made up of one or more cells and the ways cells help organisms meet their basic needs.

Give examples of organisms that consist of a single cell and organisms that are made of a collection of cells.