Parallelogram ABCD

mathxyz

Junior Member
Joined
Jul 8, 2005
Messages
112
In parallelogram ABCD, EC is perpendicular DC, angle B is congruent to angle E and angle A = 100 degrees. Find angle CDE?

MY WORK: d = degrees

Since angle A = 100d, I subtracted 100d from 180d to find angel D = 80d.
Angle D MUST = angle B because corners of parallelograms are equal.
Angle B = angle E = 80d.

I also know that EC is perpendicular to DC. Perpendicular told me that angle C must be 90d, right? Well, if this is true, then angle CDE must = angle C - Angle E.
Thus, angle CDE = 10d.

My answer is 10d.
Book's answer is 20d.

What did I do wrong?
Is my thinking okay here?
 
You still haven't told us where 'E' is. Is it on segment AB? Is it in Michigan? Is it part of the parallelogram or outside, somehwere?

Reference to 'Angel C' is insufficient. Do you mean Angle(BCE), Angle(BCD), or Angle(ECD)? Again, I'm just guessing where 'E' is.

Angle(BCE) may be 10°, but you are asked for Angle(CDE). That's a whole different animal.

At the moment, I'm not seeing how to find the measure of Angle(CDE), but since I really don't know where 'E' is, or what you mean by 'Angle(C)', I'll wait for better information.
 
mathxyz said:
In parallelogram ABCD, EC is perpendicular DC, angle B is congruent to angle E and angle A = 100 degrees. Find angle CDE?

Where in **** is E?
On AB, right?
So what's angle E? Do you mean angle CED?

Why don't you take the time to draw a diagram and ensure
your question makes sense...
 
hey

To tkhunny:

You still haven't told us where 'E' is. Is it on segment AB? Is it in Michigan?

(no need to put sarcastic)

Is it part of the parallelogram or outside, somehwere?

Here is my BEST MAP of the parallelogram ABCD:

Angle A = top left corner
Angle B = top right corner
Angle D = lower left corner (below angle A)
Angle C = lower right corner (below angle B)

Angle C lies between angle B and angle E.

Angle E is outside parallelogram ABCD.

Can you sketch the above and tell me why the answer is x = 20 degrees?

Angle C is a right angle.

Angle C, E and D = a right triangle.

Segment DE is the hypotenuse of the right triangle.
 
I'm just not happy at all with our relationship. I get to speak freely, too. Is that fair enough? Just plain old give it a rest, will you? I'm just asking a question. I get to have a personality, too. Is that fair enough? I prefer to have a personality that's a little lighter and a little less formal. You should try it. Just answer the question or don't. It's up to you. But stop attacking me (if you know what I mean). Stop CHOOSING to take offense. There is NONE intended. Just stop it, now! No one is forcing you to be offended. You are doing it yourself. Examine yourself and put an end to it this minute.

We're trying our hardest to help you, here. You are quite a burden on limited resources. Is that fair to other students? You continue to fail to give any sort of reasonable feedback that could be useful. Once in a while you show something up front. That's a start. How are we supposed to work with that? It's time for YOU to switch over to reasonable. We've been waiting for you for some time. You do not get to be incorrigable and uncooperative and cry foul every time someone else even remotely suggests that you might be the problem. Time for you to grow up, I think.

You can not imagine how difficult it is for me to write this, but I really feel that it is time to lay it out on the table. I am your friend. Hear the truth from me. I am NOT your enemy. I want to help. Let me!

Sincerest Hope for a Brighter Day,

P.S. Your description remains inadequate. We still don't know where E is. We still don't know what Angle(C) is. Put it on a coordinate system or put it in picture. So far, it just isn't working.
 
Tkhunny, you won't get anywhere with this "person", trust me. This is like the fifth time you've given this speech to this particular "person" using all these different names. Different shells, but the insides are all the same. One word, TROLL!
 
I've noticed a pattern, once we start to get frustrated with this person, they create a new name, and a new "life", so to speak. That's why you haven't seen Ritanyc, Greatwhiteshark, and Tony, anymore. Essentially, they are "dead", and will never be heard from again, because we got sick of seeing them, just like we're sick of Mathxyz, after barely a week! Over 100 questions in a week?!!!!
 
I wasn't sure at first...but now I agree with Jolly 100%.
 
Tkh: I have to agree with Jolly and Dennis.
You have known me for several years; I am not one to give up on a serious student, as you well know.

But come on, what are we to do with someone who has posted such a variety of questions, but thinks that one solves sin(90-x)=cos(x+40) by setting (90-x)=(x+40)! Even if we get this person to see an answer, it does not seem to carry over to the very next problem.

NO, I think Jolly and Dennis are correct.
 
Top