Question 1118091
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The shape of the water in the cone is a cone similar to the whole cone.<br>
In similar figures, the ratios of corresponding measurements of length are the same.<br>
This problem involves linear measurements: the height of the whole cone is 48cm; the height of the water in the cone is 40cm; the diameter of the whole cone is 54cm; and we are asked for the diameter of the surface of the water.  So<br>
{{{40/48 = x/54}}}
{{{5/6 = x/54}}}
{{{x = 45}}}<br>
The diameter of the surface of the water is 45cm.