The increase from 40% to 70% is 30% of the tank's full volume.<br>
30% of full volume = 0.72 m&sup3;<br><br>
Full volume = 0.72 ÷ 0.30 = 2.4 m&sup3;<br><br>
Height = Volume ÷ Base area<br>
&bull; Height = 2.4 ÷ 3.6 = \(\frac{2}{3}\) m<br><br>
Final Answer: \(\frac{2}{3}\) m