# Homework Help: Problem finding exterior angle

1. Sep 3, 2011

### 1/2"

1. The problem statement, all variables and given/known data
Triangle ABC has been inscribed in the circle with center o.E is the midpoint of arc BC.DE is the diameter.E is joined to A, B and C.D is joined to A . If angle ABC =72 degrees and angle ACB = 48 degrees,
find angle DAC.
(I have attached the diagram given in book although its not a very good one)

2. Relevant equations
-

3. The attempt at a solution
In this one what i did was,
i found angle BAC =(180-72-48)= 60 degrees
then i tried to subtend angle from the diameter to get 90 degree on the circumference but it did not help.
and i found the other angles like angle BEA=48 degrees and angle DEC= 72 degrees by the theorem the a chord extend equal angles on the circumference. But i can't get any further than this .Please help.
the answer given in my book is 60 degrees.
If I am going wrong somewhere please do let me know.
Thank you.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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2. Sep 3, 2011

### tiny-tim

hi 1/2"!

use the theorem that opposite angles subtended from the same chord (ie opposite angles of an inscribed quadrilateral) add up to 180°

3. Sep 3, 2011

### 1/2"

I think i have already done it.
can you please be alittle more elaborate?
thanks.

4. Sep 3, 2011

### tiny-tim

i'm confused … if you've already done it, what's the problem?

and i've given you the full theorem … what is there to elaborate further?

5. Sep 3, 2011

### 1/2"

I am really sorry to confuse you.
Could you give a more direct clue how to get the angle DAC?
and i am really sorry.

6. Sep 3, 2011

### 1/2"

Thank you
but i have got it.