Lab #3 Assignment
M 333 L
The nine (9) special points on the Nine-Point Circle of
the feet of the altitudes from vertices A, B, and C to the sides (perhaps extended) of
the triangle opposite vertices A, B, and C, respectively.
the midpoints of the sides of the triangle opposite vertices A, B, and C, resp.
the midpoints of the segments connecting the orthocenter H to vertices A, B, C, resp.
The color specifications are only for your sketches as they appear on your computer monitor.
a color printer is not available, then black and white printouts are acceptable.
The Sketchpad Assignment is to perform the following steps:
(Note: Only those objects assigned to be constructed should remain visible.
Any other points and
lines constructed in the process of constructing the assigned objects must be hidden in the final sketch.)
1) In a new sketch, construct three (3) free non-collinear points and label them A, B and C.
2) Construct three (3) dashed blue complete lines, each passing through two of the three points; that is,
AB BC and AC
3) Construct three (3) dashed red complete lines, each passing through one of the three points and
perpendicular to the blue dashed line passing through the other two points.
4) Construct the points which are the feet of the altitudes of
ABC and label them F
(Review the Lab #1 Assignment to recall how to put subscripts in a label.)
5) Construct three (3) thick blue segments on the sides of
ABC; that is, construct
6) Construct the midpoints of these three thick blue segments, and label as M
the midpoint of the side
of Δ ABC opposite A,
label as M
the midpoint of the side of Δ ABC opposite B, and label as M
midpoint of the side of
ABC opposite C.
7) Construct the orthocenter of
ABC and label the orthocenter point H. (Note: no new lines need to
be constructed. You only need to construct the point of intersection of two previously constructed lines.)
8) Construct the circumcenter and label the circumcenter point S.