There are 5 points A, B, C, D, and E distributed on the straight line in turn. It is known that AB=19cm, CE=97cm, AC=BD. Then DE=how many cm.
直线上依次分布着A、B、C、D、E共5个点，已知AB=19cm，CE=97cm，AC=BD．那么DE=多少cm．
<gadget id="calculator">97 - 19</gadget>
<output>78</output>

<result>78</result>