Find the area of $\Delta ADE$ in the given figure.                                                                                             [Page No. 142]

From the figure:
Base AD = 8 cm
Distance from E to line AD = 10 cm

Area of triangle = $\frac{1}{2} \times \text{base} \times \text{height}$

$$= \frac{1}{2} \times 8 \times 10 = 40 \text{ cm}^2$$

Hence, area of triangle is $40 \text{ cm}^2$.