Geometry board guide

Try drawing a segment yourself:

Step 1 of 9

A segment:

First choose a tool, then tap the two ends.
A tap on a point picks it; a tap on a side puts a new point on it.
The new point can be dragged with the arrow tool – along the side, and the segment moves with it.

A parallel:

Pick a point and a line, in either order.
The parallel segment goes through the point; each of its ends drags along the parallel line.

A perpendicular from a point to a side is the altitude:

The point where it meets the side gets a letter of its own.
The right-angle mark comes by itself.

Equal sides:

A tap between two points on a side marks only that part.
Each tap more adds a tick; the fourth takes them away.

An angle mark:

Tap inside the angle, near its vertex.
Equal angles get the same letter (the label tool), or the same number of ticks on the arc (the equal-sides tool).

When several lines leave a vertex, one tap is inside several angles:

A list of them opens, from the smallest up.
Each angle lights up on the board while you point at it.

A label – on a side, an angle or a point you drew:

Its box has keys for Greek letters, degrees and signs.

Delete takes only what you drew, and what is built on it.
Undo brings back what was deleted.

Zooming changes only the view.
The last button brings back the whole figure.
On a touch screen, zoom with two fingers.