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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

1685.0. "Build a triangle from ..." by TAV02::NITSAN (One side will make you larger) Wed Oct 28 1992 13:23

Can you please help a "foreigner" like myself with some English terms?
Having a triangle ABC, how do you call in English:

 1. The line segment that connects A with the mid point of BC?
 2. The line segment that splits the angle in A exactly in the middle?
 3. The line segment that starts at A and has a right angle with BC?
     (is it called the "height" that starts at A?)

and the real question I saw long ago (without the solution) is:
Given the above three segments, how do you *build* (is that the correct
term again?) the triangle?

/Nitsan
T.RTitleUserPersonal
Name
DateLines
1685.1how I'd word thingsHANNAH::OSMANsee HANNAH::IGLOO$:[OSMAN]ERIC.VT240Wed Oct 28 1992 13:5333
Suppose triangle is

			A


		B	x z  y		  C

Assume angle AxB is 90, and that angle yAC equals angle yAB and that segment
Bz equals segment zC in length.

I'd describe line Ax by saying

	Drop a perpendicular from A to line BC.  This Ax line is a height of
	the triangle.

I'd describe line Ay as the bisector of the angle BAC.  Note that we use the
word "line" here to indicate what Euclidean geometry calls a "line segment",
but in common English, a straight set of points from one point to another is
commonly called a "line", as in "please draw a straight line from A to B".

I'd describe z as the midpoint of segment BC, but I don't know of a common
word for segment Az.  I would say "draw a segment from A to the midpoint of
BC".

If you want to pose a construction problem, I might pose it like this:

	Given point A, and the three segments, Ax, Ay, and Az, where Ax is the
	height of a triangle ABC, and Ay bisects angle BAC, and z is the
	midpoint of segment BC, construct points B and C, using only a
	straight edge and compass.

/Eric
1685.2I can't remember how to solve it, but here's how to ask it!SGOUTL::BELDIN_RD-Day: 154 days and countingWed Oct 28 1992 14:0914
    1. Median to BC
    2. Bisector of angle BAC
    3. Height (relative to BC as base).
    
    We would understand "build" but most would say "construct".
    
    If the vertices of a triangle are labeled A, B, and C, and 
    you are given:
    	AM, the median to BC, 
    	AP, the bisector of <BAC, and 
    	AH, the height above BC,
    how would you construct <| ABC?
    
    
1685.3AddendumVMSDEV::HALLYBFish have no concept of fire.Wed Oct 28 1992 14:301
    3.  I've also heard the term "altitude" used instead of "height".
1685.4SGOUTL::BELDIN_RD-Day: 154 days and countingWed Oct 28 1992 14:443
    Altitude is probably more common than height, in fact.
    
    Dick