See Examples 5-7 . If you do not have a calculator, use 3.14...

See Examples $5-7 .$ If you do not have a calculator, use 3.14 as an approximation of $\pi .$ Answers may vary slightly depending on which approximation of $\pi$ is used. Straws. Find the volume of a 150 millimeter-long drinking straw that has an inside diameter of 4 millimeters. Round to the nearest cubic millimeter.

See Examples $5-7 .$ If you do not have a calculator, use 3.14 as an approximation of $\pi .$ Answers may vary slightly depending on which approximation of $\pi$ is used.
Straws. Find the volume of a 150 millimeter-long drinking straw that has an inside diameter of 4 millimeters. Round to the nearest cubic millimeter.

Key Concepts

Rounding

Rounding is the process of adjusting a numerical result to a desired degree of precision, such as to the nearest unit. This is important for presenting a clear and practical answer, especially when dealing with measurements in contexts where slight variations are acceptable.

Measurement Consistency

Ensuring that all dimensions are expressed in the same unit is crucial for accurate computation. When calculating volume, it is important that measurements like diameter, radius, and height are consistent so that the final result accurately represents the physical space occupied.

Volume of a Cylinder

This concept involves calculating the space inside a cylindrical object using the formula V = ?r²h. Understanding this formula is fundamental in geometry for finding volumes of circular objects, where r is the radius of the circular base and h is the height or length of the cylinder.

Using Approximations for ?

In many practical problems, ? is approximated as 3.14 to simplify calculations when a calculator is not available. This approximation provides a reasonable estimate for the area or volume involving circles, helping to achieve workable results in real-world situations.

Transcript

00:01 In this problem, we're being asked to find the volume of a 150 millimeter long drinking straw that has an inside diameter of four millimeters.

00:09 And then we're going to round to the nearest cubic millimeter.

00:12 In other words, the nearest whole number.

00:13 Well, let's think about what a straw looks like.

00:16 Here's my, as good as i can draw it, picture of a straw, which essentially is a cylinder.

00:22 Well, if we're being asked to find the volume of the cylinder, remember, to find the volume of cylinder is the formula of v equals pi, r, squared h.

00:33 Well, we were told that it's 150 millimeters long.

00:37 Well, that's going to represent the height.

00:39 Now, we were told that the diameter is four millimeters.

00:42 Well, remember, the diameter would be the whole length across.

00:47 But in our formula, we need the radius, which is half of the diameter.

00:50 The radius is only going from the middle to the edge.

00:55 So, it would be half the diameter.

00:58 So if our diameter was four, our radius would be half of it, which would be 2 millimeters.

01:04 Well, now that we know the radius and the height, we simply need to substitute those values into the formula to find the volume.

01:11 So we're going to have the volume is equal to pi times the radius, which remember we said was 2 squared, times the height, which was 150...