Question 1206679
<pre>
{{{drawing(400,2009/9,-1,17,-1,9,

circle(4,4,3), circle(12,4,3), 
line(1,4,7,4),line(4,4,4,7), line(9,4,15,4),line(12,4,12,7), 
locate(.5,4.3,A),locate(8.5,4.3,A),
locate(7.15,4.3,C), locate(15.15,4.3,C),
locate(3.88,4,B),locate(11.88,4,D),
locate(3.88,7.7,D),locate(11.88,7.7,B),
red(rectangle(3.6,4,4,4.4)),line(9,4,12,7),
red(arc(12,7,1.6,-1.6,225,270))


)}}}

If you mean the figure on the left, angle ABD is 90<sup>o</sup>.
If you mean the figure on the right, angle ABD is 45<sup>o</sup>.

Edwin</pre>