Geometry Expressions

Slope App

We create an app which allows the user to drag a right angled triangle over a picture, and thus estimate the slope of a cliff face.

We draw a triangle on top of our picture.

Picture 1

Constrain one line to be horizontal and the other to be vertical.

Constrain the coordinates of two points, leaving them as variables.

Picture 2

Measure the lengths of the horizontal and vertical lines and the slope of the slant line.

Picture 3

When we create the app, we specify that the coordinates variables should be specified by dragging.

Picture 4

Here is the resulting app.