Application Guide

268 Geometry Application
• If the center of a square is close to an existing point, the square snaps to that
point.
Drawing Polygons
To create a polygon, tap or click a succession of existing points, ending on the first
point you tapped.
Using MathDraw to Create Equations
In the Graphs view, MathDraw attempts to recognize certain gestures as functions for
analytic parabolas.
Note: The default step value for quantization of the parabola coefficients is 1/32. The
denominator of this fraction can be redefined using a variable named ti_gg_fd.par_
quant. You can change the step value in the current problem by setting this variable to
a value greater or equal to 2. A value of 2, for example, produces a step value of 0.5.
Using MathDraw to Measure an Angle
To measure the angle between two existing lines, use the touchscreen or mouse to
draw a circle arc from one of the lines to the other.
• If the intersection point between the two lines does not exist, it is created and
labeled.
• The angle is not a directed angle.
Using MathDraw to Find a Mid-point
To create a point midway between two points, tap or click point1, point2, and then
point1 again.
Using MathDraw to Erase
To erase objects, use the touchscreen or mouse to drag left and right, similar to the
motion of erasing a whiteboard.
• The erasure area is the bounding rectangle of the erasure gesture.
• All point objects and their dependents inside the erasure area are removed.