The shaded triangle lies within rectangle JKLM (12 cm by 9 cm).<br><br>
&bull; The base of the triangle is along side JM or KL of the rectangle<br>
&bull; From the figure, the base of the shaded triangle is 9 cm (breadth of rectangle)<br>
&bull; The height of the triangle is 12 cm (length of rectangle)<br><br>
Final Answer: Base = 9 cm, height = 12 cm