Construct two lines with specific angle in between

[teerasak]

In Geometry app, there are set of geometry elements e.g line, circle, etc.

If I want to draw two lines (or perhaps rays) meeting at endpoint with specified angle (for example, drawing two lines meeting at the endpoint with angle between two line of 20 degree).

Any idea to do that in Geometry app?

[roadrunner]

Here is how I did it:

"GA:= point(-4.,−4.2); // c(FF000000) v(1) \nGB:= point(7.,3.3); // c(FF000000) v(1) \nGD:= circle(GA,GB-GA); // c(FF000000) v(1) \nGE:= element(GD,0); // c(FF000000) v(1) a(t(1) s(3) p(3) b(0) e(6.2832) S(0.2)) \nGG:= line(GA,GE); // c(FF000000) v(1) \nGH:= element(GD,20/180*π); // c(FF000000) v(1) a(t(1) s(3) p(3) b(0) e(6.2832) S(0.2)) \nGI:= line(GA,GH); // c(FF000000) v(1) \n"▶Instruction

angle(GA,GE,GH)

Perhaps someone else can come up with a more direct way to do it.

-road

[Albert Chan]

I don't know if this work with HP Prime, but I did it in XCas.

line1 := line([1,1], [3,4]);
line2 := line([1,1], slope = tan(20/180*pi + atan(slope(line1))))