Show that angle BOC is $0.691$ radians

Question

What i tried.

Since we are given the gradient of $AC$ is $\frac{9}{25}$, thus length $AO$ is $3.15/9*25=8.75$ while length $AC$ is $9.299$ by Pythagoras theorem. Next i can find angle $CAO$ using the trigonometric formula which gives 36.23 rad. Angle ACO can then be found next.

I unsure how to continue from here. Could anyone explain. Thanks

Answer 1

Guide:

• After you found $\angle ACO$, use the property that $OBPC$ is a sector, and hence we know that $\angle CBO= \angle ACO$.

• Use the property that angles in $\triangle CBO$ sums up to $\pi$.

Remark:

• We do not need length information to find the angle.