IXL | Identify proportional relationships by graphing

Roxanne is measuring the diameter and the radius of different-sized circles. A circle with a 3-inch radius has a diameter of 6

inches.

A circle with a 4-inch radius has a diameter of 8

inches.

In this relationship,

represents the radius in

inches,

and

represents the diameter in

inches.

Graph two points for this relationship and the line passing through them.

x-axis, Radius in inches, y-axis, Diameter in inches. Coordinate plane graph with 1 quadrants, x-axis coordinates from 0 to 10, y-axis coordinates from 0 to 10.

According to the graph, do x and y have a proportional relationship?

yes

ref_doc_title.

Learn with an example

question

Every spring, Pablo plants colorful flowers in his garden. This year, he decides to plant petunias. He buys them at the garden store, brings them back home, and starts planting. After working in his garden for 5

minutes,

Pablo has planted 5

petunias.

After working for 7

minutes,

he has planted 7

petunias.

In this relationship,

represents the amount of time (in

minutes)

Pablo has been working in his garden, and

represents the number of petunias he has planted.

Graph two points for this relationship and the line passing through them.

According to the graph, do x and y have a proportional relationship?

yes

key idea

The graph of a proportional relationship between

and

is a straight line passing through the origin,

(

)

solution

To find two points for this relationship, look for clues in the problem related to

and

y-values.

minutes,

Pablo has planted 5

petunias.

After working for 7

minutes,

he has planted 7

petunias.

In this relationship,

represents the amount of time (in

minutes)

Pablo has been working in his garden, and

represents the number of petunias he has planted.

The problem describes the points (5, 5) and (7, 7). Plot these points on the graph.

To determine whether x and y have a proportional relationship, see if the line through these points passes through the origin, (0, 0).

The points are on a line that passes through the origin. So, x and y have a proportional relationship.

Looking for more? Try these:

Lesson: Proportional relationships

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LL.3Graph points on a coordinate plane

Lesson: Proportional relationships

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