## Search Results

### IGD: Simson Line - Orthocenter

9-12
Use this tool to explore how the Simson line of a triangle is related to the orthocenter.

### Isometric Drawing Tool

3-5, 6-8, 9-12
Use this interactive tool to create dynamic drawings on isometric dot paper.

### Line of Best Fit

6-8, 9-12
Use this activity to practice how to enter a set of data, plot the data on a coordinate grid, and determine the equation for a line of best fit.

### Name Letters

3-5, 6-8, 9-12
Use this activity to practice solving systems of equations. Use this tool to check students' answers.

### Scale Factor

6-8, 9-12
Use this applet to investigate how changes in the scale factor influence the ratio of perimeters and the ratio of areas between two figures.

### Proof Without Words: Completing the Square

9-12
This applet gives a proof of completing the square "without words" using geometry.

### Axonometry: Applying Complex Numbers to Art

9-12
In this lesson, students examine and draw representations of cubes and then learn how to analyze these representations using complex numbers. Students use what they know about operations on complex numbers to see if a drawing is an accurate representation of a cube. They also learn how to generate complex numbers that will produce such representations.

### Work to a Conclusion

9-12
Sea gulls and crows feed on various types of mollusks by lifting them into the air and dropping them onto a rock to break open their shells. Biologists have observed that northwestern crows consistently drop a type of mollusk called a whelk from a mean height of about 5 meters. The crows appear to be selective; they pick up only large-sized whelks. They are also persistent. For instance, one crow was observed to drop a single whelk 20 times. Scientists have suggested that this behavior is an example of decision-making in optimal foraging.

### The Regression Line

9-12
Interactive computer-based tools provide students with the opportunity to easily investigate the relationship between a set of data points and a curve used to fit the data points. As students work with bivariate data in grades 9-12, they will be able to investigate relationships between the variables using linear, exponential, power, logarithmic, and other functions for curve fitting. Using interactive tools like the one below, students can investigate the properties of regression lines and correlation.

### The Effects of Outliers

9-12
Interactive computer-based tools provide students with the opportunity to easily investigate the relationship between a set of data points and a curve used to fit the data points. As students work with bivariate data in grades 9-12, they will be able to investigate relationships between the variables using. Using interactive tools like the one below, students can investigate the properties of regression lines and correlation.