Question

In the adjoining figure `O` is the centre of the circle and `angleAOB=100^(@)`. Find the value of `angleBCD`.

Answer 1

At point `O` ,
`angle AOB +"reflex"angle AOB=360^@`
`rArr100^@+"reflex" angle AOB =360^@`
`rArr"reflex " angle AOB=360^@-100^@`
`260^@`
Now, arc APB Subtends angles at
centre = reflex `angleAOB`
remaining part `=angle ACB`
`angle ACB =(1)/(2) xx"reflex "angle AOB`
`=(1)/(2)xx260^@`
`=130^@` .