F4 Circles (3): angles

According to " $\angle$  at centre = 2 $\angle$  at circumference",  $\angle$ OAC = 2  $\angle$ OBC.

• True

• False

According to " $\angle$ at centre = 2 $\angle$ at circumference", $\angle$ AOB = 2 $\angle$ ACB.

• True

• False

According to " $\angle$ at centre = 2 $\angle$ at circumference", $\angle$ AOB = 2 $\angle$ ACB.

• True

• False

According to " $\angle$ at centre = 2 $\angle$ at circumference", $\angle$ AOB = 2 $\angle$ ACB.

• True

• False

In the figure,  $m$  =

•  $x+y$  .
  

•  $2x+2y$  .
  

•  $90\degree-x-y$  .

•  $180\degree-2x-2y$  .

In the figure, x =