## Monday, November 9, 2015

### HP Prime Geometry App Tutorial Part 8: Rotating Triangles

HP Prime Geometry App Tutorial Part 8:  Rotating Triangles

Today’s lesson will show how to rotate a triangle given an angle.  The angle is in a counter-clockwise direction.

For the purpose of this lesson, we will set the HP Prime in Degrees mode.

Draw the Triangle

1.  Set the calculator to Degrees mode.  Draw a triangle with vertices (4,4), (4, -4), and (8, 0).

Rotate the Triangle

2.  Press (Cmds), 7 for Transformation, 3 for Rotation.
3.  Select the reference point.  In our example, let’s make this point (0,0) and press [ Enter ].
4.  You are asked for an angle.  Enter 90 for 90°.  Press [ Enter ].

More Rotation

5.  Repeat steps 2 through 4, for angles of 180 and 270.

Thank you.  Until next time, have a great day!

Eddie

This blog is property of Edward Shore.  2015.

1. Hi Edd, Im always fallowing your posts and learning a lot about programming and many other things .Its very very helpful.
I need some help.. i would like to know the Syntax to acces to Geometry app. For exampe, Plot a Matrix..., i know there is a command "plotlist" inside the app but, how can i do that by programming..is it possible?

Thank you very much
Sorry for my poor english :(

1. Suzuki,

Unfortunately, geometry commands are not user-friendly and don't work too well (if at all) in programming.

The fastest way to plot lists in a program setting is to switch over the Statistics 2Var app (2-variable statistics app). This one sets the plot screen to Autoscale:

EXPORT LISTPLOT(listx,listy)
BEGIN
// Use Statistics 2 App
STARTAPP("Statistics 2Var");
C1:=listx;
C2:=listy;
CHECK(1);
// Autoscale in Stat 2 plot
STARTVIEW(9);

END;

If you want more control over the view screen x=[xa,xb] and y=[ya,yb], use LSTPLT2:

EXPORT LSTPLT2(listx,listy,xa,xb,ya,yb)
BEGIN
// Use Statistics 2 App
STARTAPP("Statistics 2Var");
C1:=listx;
C2:=listy;
CHECK(1);
// Set the plot screen
Xmin:=xa; Xmax:=xb; Ymin:=ya; Ymax:=yb;
// 1 is plot view in Stat 2 (v. 8151)
STARTVIEW(1);

END;

Hope this helps,
Eddie

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