GeoScratch

 

#1 What tools are available?

• ​Arrow Tool

move over a shape to select or deselect the shape and show the properties of the shape. Selecting any other tool or arrow tool again deselects everything.

• Lasso Tool

draw a freehand path which selects all the shapes inside the path. The selection from the Lasso tool can be fine tuned using the Arrow Tool.

• Point Tool

Used to create a new placeholder point or drag an existing point. If the initial touch is within certain distance of an existing point, it selects the point. It is useful to place a point at the desired location first before constructing a line or circle. Turn on the "Snap to Point" option in settings to make the new line or circle constructed from the existing point.

• Line Tool

Draws a line segment. Set the line width and color first, touch the screen at the start point and drag to the end point to create the line. 

• Circle Tool

Draws a circle. Set the line width and color first, touch the screen at the center of the circle and drag to set the radius of the circle.

• Freehand Tool

A premium feature which allows drawing freehand notation on the diagram

 

 

#2 How to construct perpendicular bisector of a line segment​​​?

Draw the line segment first if it doesn't exist yet. Select the "Point" tool and make sure that "Snap to point", "Snap to shape", "Snap to bisector" and "Snap to direction" are turned on. Touch the screen to create a new point, drag the point close to the line segment and it would snap to the bisector of the line segment which is marked by a cyan tick mark on the line segment. After creating the point, select the "Line" tool. Touch the screen close to the point created in the first step and start dragging the line. The line will snap to the perpendicular direction of the line segment with perpendicular symbol at the intersection.

 

#3 How to construct angle bisector between two line segements?​

Turn on "Snap to point", "Snap to intersection", "Snap to length" and "Show loupe". Use "Circle" tool and use the common point of the two line segments as the center of the circle and make sure that the circle intersects with both line segments. Draw one circle each from each of the intersection points on the two line segments and make sure that both circles have the same length and intersects. Since the "Snap to length" option is on, the circles are snapped to five units boundary and just make sure the end point of the circles are at relatively empty spaces to make the length snapping to work.

 

#4 How to extend a line segment​

Turn on "Snap to point" and "Snap to direction". Use the point tool to select the point that you want to extend. When you start dragging the point, the line snaps to the original direction of the line segment.

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​#5 What are those options in the settings menu?​

• ​Snap to point

This option snaps the current touch location to a nearby intersection. 

• Merge points

To turn on "Merge points", "Snap to point" need to be on. Instead of creating new point, it reuses the existing point that is snapped with the "Snap to point" option

• Snap to intersection

This option snaps the current touch location to a nearby intersection.

• Snap to direction

When creating a new line or dragging an end point of a line, it snaps to integer degree, multiples of 15 degree. When extending a line segment from one end point, it snaps to the original direction of the line segment. If the other end of the line segment being edited lies on a different line, it also snaps to the direction that is perpendicular to that line.

• Snap to length

Snaps the length of line segment or radius of circle to every 5 units

• Snap to bisector

In "Line Tool", when the end point of a line is dragged to close to a line segment, the midpoint of the line segment shows with a magenta tick and the end point snaps to it if it is close enough.

• Snap to perpendicular

In "Line Tool", when the end point of a line is dragged to close to a line segment, the point where the edited line forms perpendicular angle with the line segment shows a purple circle and the end point snaps to it if it is close enough.

• Snap to tangent

Ihen dragging a point using the "Point tool", "Line tool", or "Circle tool", the point snaps to a shape if the finger location is close to one.

• Snap to shape 

When dragging a point in "Point tool", "Line tool" and "Circle tool", the point snaps to a shape if the finger location is close to one.

• Show loupe

Show what's under the finger so that you can place the point at any location. Also displays the attributes of the line or circle you are currently drawing.