Triangle Centers
Incenter Construction
1) Use the POINT TOOL and mark point D on segment AB.
I would place it closer to A than B
2) Use the COMPASS TOOL, create a circle with radius DA and center A.
3) Use the POINT TOOL and mark where the circle intersects AC as E.
E should be a black dot not purple
4) Use the COMPASS TOOL, create a circle with radius DE and center D.
5) Use the COMPASS TOOL, create circle with radius DE and center E.
6) Use the POINT TOOL and mark where circles D and E intersect inside the triangle as F.
F should be a black dot not purple
7) Use the ray tool and create ray AF
Repeat these 7 steps from vertices B and C.
You can drag any purple point to help separate constructions.
Using the POINT TOOL, mark the incenter as M.
Point M should be black not purple
YOU SHOULD BE ABLE TO DRAG ANY PURPLE POINTS AND POINT M WILL REMAIN THE INCENTER
Construction #1 (INCENTER)
Circumcenter Construction
1) Use the POINT TOOL and mark point D on segment AB closer to B
2) Use the COMPASS TOOL, create a circle with radius DA and center A
3) Use the COMPASS TOOL, create a circle with radius DA and center B
4) Use the POINT TOOL and mark where circles A and B intersect as E and F
Points E and F should be black points, not purple.
If you cannot see the two intersections move any purple point until you can see.
5) Use the LINE TOOL and create line EF
Repeat these 5 steps on sides BC and AC.
Using the POINT TOOL, mark the circumcenter as M.
Point M should be a black point, not purple.
YOU SHOULD BE ABLE TO DRAG ANY PURPLE POINTS AND POINT M WILL REMAIN THE CIRCUMCENTER
Construction #2 (CIRCUMCENTER)
Centroid Construction
1) Use the POINT TOOL and mark point D on segment AB closer to B
2) Use the COMPASS TOOL, create a circle with radius DA and center A
3) Use the COMPASS TOOL, create a circle with radius DA and center B
4) Use the POINT TOOL and mark where circles A and B intersect as E and F
Points E and F should be black points, not purple.
If you cannot see the two intersections move any purple point until you can see.
5) Use the LINE TOOL and create line EF
6) Use the POINT TOOL and mark point G where the line intersect side AB.
G should be blank dots not purple
6) Use the SEGMENT TOOL and create median CG
7) Use the MIDPOINT TOOL to mark the midpoint of segment AC as H.
Select the MIDPOINT TOOL, then click on A, then C
8) Use the MIDPOINT TOOL to mark the midpoint of segment BC as I.
Select the MIDPOINT TOOL, then click on B, then C
9) Using the POINT TOOL, mark the centroid as J.
Point M should be a black point, not purple.
YOU SHOULD BE ABLE TO DRAG ANY PURPLE POINTS AND POINT J WILL REMAIN THE CENTROID
Construction #3 (CENTROID)
Orthocenter Construction
1) Use the COMPASS TOOL, create a circle with radius CA and center C
2) Use the POINT TOOL and mark where circle C intersects AB as D
D should be a black point, not purple
3) Use the COMPASS TOOL, create a circle with radius AD and center D
4) Use the COMPASS TOOL, create circle with radius AD and center A
6) Use the POINT TOOL and mark where circles A and D intersect as E
7) Use the LINE TOOL and create altitude CE
8) Use the PERPENDICULAR LINE TOOL click B, then side AC to create the 2nd altitude
9) Use the PERPENDICULAR LINE TOOL click A, then side BC to create the 3rd altitude
10)Using the POINT TOOL, mark the incenter as F.
YOU SHOULD BE ABLE TO DRAG ANY PURPLE POINTS AND POINT F WILL REMAIN THE ORTHOCENTER