Use a geometric tool to draw a circle. Draw and measure a radius and a diameter of the circle.

Here is a circle with center \(H\) and some line segments and curves joining points on the circle.

A circle, with a center labeled H. Around the edge of the circle are points labeled A, B, C, D, E, F, and G. A line extends from point A through center H to point E. A curved extends from point B to center H. A line extends from point C to point E. A line extends from point D through center H to point G. A curved line extends from point F to center H.

Identify examples of the following. Explain your reasoning.

1. Diameter

2. Radius

Lin measured the diameter of a circle in two different directions.

• Measuring vertically, she got 3.5 cm.
• Measuring horizontally, she got 3.6 cm.

Explain some possible reasons why these measurements differ.

A small batch of lemonade used \(\frac{1}{4}\) cup of sugar added to 1 cup of water and \(\frac{1}{4}\) cup of lemon juice. A larger batch is going to be made using 10 cups of water. How much sugar should be added so that the large batch tastes the same as the small batch?

The graph of a proportional relationship contains the point \((3, 12)\). What is the constant of proportionality of the relationship?