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MA19.7.20
Explain the relationships among circumference, diameter, area, and radius of a circle to demonstrate understanding of formulas for the area and circumference of a circle.

Explain the relationships among circumference, diameter, area, and radius of a circle to demonstrate understanding of formulas for the area and circumference of a circle.

### Unpacked Content

## UP:MA19.7.20

### Vocabulary

- Diameter
- Radius
- Circle
- Area
- Circumference
- π

### Knowledge

Students know:

- that the ratio of the circumference of a circle and its diameter is always π.
- The formulas for area and circumference of a circle.

### Skills

Students are able to:

- use the formula for area of a circle to solve problems.
- Use the formula(s) for circumference of a circle to solve problems.
- Give an informal derivation of the relationship between the circumference and area of a circle.

### Understanding

Students understand that:

- area is the number of square units needed to cover a two-dimensional figure.
- Circumference is the number of linear units needed to surround a circle.
- The circumference of a circle is related to its diameter (and also its radius).