Question 356818
An isosceles trapezoid had an angle measuring 138°. What are the measure of all the other angles

<pre>

{{{drawing(800,200,-3,7,-.5,1,  

line(-cos(42*pi/180),0,0,sin(42*pi/180) ),

line(-cos(42*pi/180),0,2+cos(42*pi/180), 0 ),

line(2+cos(42*pi/180),0, 2,sin(42*pi/180) ),

line(2,sin(42*pi/180),0,sin(42*pi/180) ),   
red(arc(0,sin(42*pi/180),.5,-.23,240,360) ),

locate(0, .55,"138°")  )}}}

Since the trapezoid is isosceles, the angle on the upper right 
is also 138°.

The lower left angle is supplementary to 138°, so it is 180°-138°
or 42°.

Since the trapezoid is isosceles, the angle on the lower right 
is also 42°.

Edwin</pre>