The density of lead is 11.4grams / c * m ^ 3 . If a lead pipe has an outer diameter of 7.4

Answer 1

You didn't complete your question. If your question is supposed to be "How do I calculate the mass of a lead pipe?" then take a look at this sketch:

To calculate the mass of the pipe, multiply the volume (in cm³) by the density (in grams/cm³) and you will get the mass in grams.

To find the volume, you would find the area of the cross section (the shaded blue part on my sketch) and multiply it by the length. The pipe has an outer radius (r_o), which I show in red, and an inner radius (r_i), which I show in blue.

r_o = 1/2 the outer diameter so it would be 7.4/2 or 3.7 (maybe cm??)

Then to find the area of the cross section (the end of the pipe):

It is made of two circles, one inside the other. Each circle has an area calculated by π•r². To find the area of just the shaded portion (shaded in blue on my sketch), find the area of the large circle and subtract the area of the small circle. So π•r_o² - π•r_i². Then multiply that answer by the length to get the volume of the pipe. Make sure all the units are in "cm".

Again, once you get the volume, multiply it by the density 11.4 grams/cm³ to get the mass in grams