area trapeze

N

nick2013

New member
Joined
Aug 9, 2013
Messages
10
Hello,

I wrote a previous thread on a similar topic, I have a new problem kind of similar and I'm again struggling to resolve it.

Trapeze.jpg

Basically, I'm trying to find the z-coordinate of point D.
I know the lengths AB, BC and CA, I know the angle BDE and I know that the area of the trapeze (area B) is more or less equal to the area of the triangle (area A) But I don't really know how to find the length BD.
I know the problem is more complicated (since the z -coordinate of point C is not 0), but it is an approximation.
I hope someone can help me to resolve this !

Thank you and happy holidays
 
trapeze

in the last figure: D(0,Z1) and A(0,Z-y) how does that the same?

I have the coordinate of A,B and C. I'm looking for the y-coordinate of D, so because i know the angle BDE, I can draw my line.
The dotted line just represent the previous AC line before rotation of the right triangle.

I'm trying to built a trapeze (area B) on top of the triangle in part 3, with limited information. How can I do that?



Denis said:
WHO d'heck drew that diagram...you? Your teacher?
How can A and D have the same co-ordinates?!

Are you simply starting off with a right triangle,
then adding inside a straight line parallel to the hypotenuse,
such that the 2 areas created by this line are equal ?
Click to expand...
 
trapezoid

A and B are not symmetric (this is maybe just because of my sketch).

There is no relation between C and E. The x-axis is bent so i cannot really determine the angle.

That's why I was trying to figure out where D should lie more or less. But I have two unknowns.. the large base of the trapezoid and its height.. that is where i'm stuck..

Romsek said:
is there some reason you can't slide the whole diagram up so that C lies on the x axis? Yes A and B won't be symmetric about 0 any longer but I still think it will be easier to solve.

What's the relationship of (z-y1) and z2? I.e. the y coordinates of points C and E?

Maybe if you just give us the whole story we can help better. Where is this problem coming from?
Click to expand...
 
Last edited:
trapezoid

Yes

denis said:
Code: 
e


b


 

c                  a          d
right triangle abc; the sides are givens.

Ca is extended to cd, cb is extended to ce, such that ab is parallel de.
Given is angle dec.

Area of trapezoid abed = area of triangle abc.
Calculate the length of be.

Is that the same as your problem?!
Please answer yes or no:confused:
Click to expand...
 
trapezoid

Thank you Denis and Romsek, this was very helpful.. I should have reminded I could use the ratios to calculate the lengths..
 
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