Start by finding the volume of one water balloon.

Recall how to find the volume of a sphere:

Plug in the given value for the radius.

Now, since one water balloon will require  of water, divide the total volume of water by this value to find how many balloons can be filled.

Since the question asks for the number of complete balloons that can be filled, we will have to round down to the nearest whole number, .

Consider a tube which is 3 ft wide and 18 ft long.

Find the volume of the largest sphere which could fit within the tube described above. 

To find the volume of a sphere, we simply need its radius

Now, the largest sphere which will fit within the tube will need to have a radius equal to the tube. Therefore, we can say our radius must be half the diameter, making it 1.5 ft.

Next, plug 1.5 ft into our formula to find our Volume

So, our answer is:

This problem is deceptively simple. In order to solve for the volume of a sphere, all you need is the formula: , where r is the radius. 

This problem has provided additional information alongside the pertinent information. We don't need to know what the circumference is if we have been provided with the radius. 

Therefore, this problem can be quickly solved for by substituting  for  in the volume formula. 

therefore, the volume of this sphere is 

This problem is deceptively simple. In order to solve for the volume of a sphere, all you need is the formula: , where r is the radius. 

This problem has provided us with the diameter, so we just need to do a little bit of work to solve for the radius. What is the relationship between radius and diameter? The diameter is twice the radius. Or in math speak: . This means we can solve for our radius by taking half of the diameter. Therefore, the radius will be  

Now that we have r, we can substitute in the value for r and solve for the volume!

This problem is very easy to solve as long as you have the volume formula for a sphere handy. 

The formula is , where r is the radius. 

The problem provides us with V, the volume. If we substitute in the volume, the only unknown in the problem is r. This is exactly what we want. 

The goal is to get r by itself. We can begin this process by dividing by .

Now we may multiply both sides of the equation by  to remove the fraction from the right side of the equals sign. This allows us to get closer to solving for r. 

Now we need to take the cubed root of each side and we will have solved for the radius!

One cubic meter of water is equal to  cubic centimeters; one-fourth of a cubic meter is 250,000 centimeters. The volume of the aquarium is 

 cubic centimeters.

Therefore, after having one-fourth of a cubic meter of water poured in, there is room left for 

 cubic centimeters of water.

The aquarium is a rectangular prism with dimensions 9 meters by 9 meters by 10.5 meters, each of which can be converted to centimeters by multiplying by 100. So the dimensions are 900 cm x 900 cm x 1,050 cm, and the volume is the product of the three, or

or

80% of this is

Each pipe fills the aquarium at 200 L per minute, so the eight pipes working together fill it at a rate of 1,600 L per minute. Divide, and the aquarium is filled at 80% capacity in

In hours, this is

so 7 hours is the correct response.

The volume of the rectangular solid can be written as:

The length times width constitutes the base of the rectangular solid, and is given in the question.

Substitute the known dimensions into the formula.

The answer is:  

Convert all the dimensions into feet.

Write the formula for the volume of the block.

Substitute the dimensions and solve for volume.

The answer is:  

Write the formula for the volume of a rectangular prism.

Substitute the dimensions into the formula.

The answer is: