Question 2
Exercise 14. The figure is made up of a semicircle and a right triangle. Given that the diameter of the semicircle is 42cm and the difference in area of region $A$ and region $B$ is $357\text{ cm}^2$, find the height of the triangle. Take $\pi=\frac{22}{7}$.
**Editorial input convention:** Use the pictured orientation: the area of A exceeds that of B by 357 square centimetres. The triangle base is the 42-cm semicircle diameter. Enter its perpendicular height in centimetres.
**Editorial input convention:** Use the pictured orientation: the area of A exceeds that of B by 357 square centimetres. The triangle base is the 42-cm semicircle diameter. Enter its perpendicular height in centimetres.