Review question

# If we know the difference in their areas, how big are these sectors? Add to your resource collection Remove from your resource collection Add notes to this resource View your notes for this resource

Ref: R9423

## Question

The figure shows two sectors in which $AB$, $CD$ are arcs of concentric circles, centre $O$ and radii $\quantity{2k}{cm}$ and $\quantity{3k}{cm}$ respectively. $A\hat{O}B$ is $\frac{3}{4}$ radian and the area $ABDC$ is $\quantity{30}{cm^2}$. Find

1. the value of $k$,
2. the difference between the lengths of the arcs $AB$ and $CD$.