In the given figure A, B, C, D are points on the circle such that <acb=400
and <dab=600
what is the measure of <dba
solution
<acb=<adb=400 (angles on same segment)
in triangle dba,
<dab=600
<adb=40o
therefore, <dba= 180-(60+40)
=80o
<acb=<adb=400 (angles on same segment)
in triangle dba,
<dab=600
<adb=40o
therefore, <dba= 180-(60+40)
=80o