Mearbles of diameter 1.4 cm are dropped into a cylindrical beaker of diameter 7 cm, containing some water. Find the number of marbles that should be dropped into the beaker so that the water level rises by 5.6 cm.

Explanation

To solve the problem, we need to find the number of marbles that can be dropped into a cylindrical beaker to raise the water level by a certain height. Here’s a step-by-step solution:

### Step 1: Calculate the Volume of Water Displaced
The volume of water displaced when the water level rises can be calculated using the formula for the volume of a cylinder:
\[ V = \pi r^2 h \]
where \( r \) is the radius of the base of the cylinder and \( h \) is the height the water rises.
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