Assuming you're talking 150mm for a inside diameter of the pipe, giving 75mm (or 7.5cm) as the radius, the cross-sectional area is A = (pi)*r2, or (pi)*(7.5cm)2 = 176.7cm2. 6 meters can be expressed as 600 centimeters. The volume is area times length, so (176.7cm2)*(600cm) = 106020 cm3. 1 cm = 1 ml, so there are 106020 ml in the pipe. 1000 ml make a liter, so the pipe holes 106.02 liters.
There are 3,902,000 liters of water in 3,902 cubic meters.
12,500 liters of water is equal to: 12.5 cubic meters.
Multiply by 1000= 185000 liters
The answer will depend on the units used for the diameter: 100 millimetres, centimetres or some other units.
350 million US gallons is about 1.32489412 × 109 liters.
42,000
1000litres
We have no way of knowing how much water is in any particular volume of space.But 2.1 cubic meters = 2,100 liters .
1 cubic meter = 1 000 liters (of water or any other liquid)
2.5 cubic meters of space is the same thing as 2,500 liters of space.
You are mixing your units. Meters are length and gallons are volume. But if you meant "liter" instead of meter, then it makes sense. There are 94,635.3 liters in 25,000 gallons (for a US liquid gallon).
9 Acres = 36,421.7 square meters. 4 feet = 1.2 meters. Area x length = volume; 36,421.7 x 1.2 = 43,706 cubic meters. Cubic meters is a volume, which can be converted to liters, 1 cubic meter is 1000 liters. So your pond has 43,706,000 Liters. 1 gallon is 3.78 liters, so divide by 3.78 and your pond has 11,545,903.7 Gallons.