Measure Menu

The Measure menu commands allow you to measure numeric properties of selected objects. The commands in the top portion of the menu measure objects’ geometric properties; the commands in the bottom portion measure analytic properties. The Measure menu also contains a powerful calculator that allows you to derive new properties by calculating relationships between existing measurements. For example, you can use Calculate to sum the measured interior angles of a triangle or compute the ratio of a circle’s measured circumference to its radius.

If you want to measure a specific property and its command is not available, make sure you have only that command’s prerequisites selected. (You may have too many or too few objects selected.)

To measure an object’s properties, select that object and choose from the available commands in the Measure menu. Sketchpad produces a measurement—a named numeric value in the proper units—as the result. When you drag or change an object that you’ve measured, the measured value changes accordingly.

Three measurements and a calculation

Each command in the Measure menu is available only when objects appropriate to that measurement are selected. In other words, like those in the Construct menu, commands in the Measure menu require certain selection prerequisites.

Here’s a summary of the selection prerequisites for each command:

To use this command:	Select:
Length	one or more segments
Distance	two points, or one point and one straight object
Perimeter	one or more polygon, arc sector, or arc segment interiors
Circumference	one or more circles or circle interiors
Angle	three points (select the vertex second)
Area	one or more interiors or circles
Arc Angle	one or more arcs, or a circle and two or three points on the circle
Arc Length	one or more arcs, or a circle and two or three points on the circle
Radius	one or more circles, circle interiors, arcs, or arc interiors
Ratio	two segments or three collinear points
Calculate	(always enabled)
Coordinates	one or more points
Abscissa (x)	one or more points
Ordinate (y)	one or more points
Coordinate Distance	two points
Slope	one or more straight objects
Equation	one or more lines or circles

Subtopics:
Length
Distance
Perimeter
Circumference
Angle
Area
Arc Angle
Arc Length
Radius
Ratio
How To Construct a Slider
Calculate
Coordinates
Abscissa (x)
Ordinate (y)
Coordinate Distance
Slope
Equation