3. In a triangle, $\beta=74^{\circ} 18^{\prime}$ and $\gamma=38^{\circ} 46^{\prime}$, and $|A C|-|A B|=2.5 \mathrm{~cm}$. Calculate the lengths of the sides $|A B|$ and $|A C|$ and round the result to two decimal places. Draw a sketch.
3. Substitute $c=b-2.5$ into the formula for the sine rule. Express $b=-\frac{2.5 \sin \beta}{\sin \gamma-\sin \beta}$ and calculate $b=7.1 \mathrm{~cm}$ and $c=4.6 \mathrm{~cm}$.

Sketch .1 point

Writing or using the sine rule 1 point

Substituting the relationship $c=b-2.5$ into the sine rule.....................................................................

Expressing $b=-\frac{2.5 \sin \beta}{\sin \gamma-\sin \beta}$.

Correct calculation $b=7.1 \mathrm{~cm}$. . .