SOLUTION: if a solid steel cylindrical rod is 8 cm in length and has a diameter of 2.5 cm and steel weigh 7.847 g/cm^3, how much does the rod weigh? round the answer to the nearest gram

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Question 1178023: if a solid steel cylindrical rod is 8 cm in length and has a diameter of 2.5 cm and steel weigh 7.847 g/cm^3, how much does the rod weigh? round the answer to the nearest gram

i know 3.149(2.5^2)(8) is for the volume ... i think... then i would multiply that answer by the 7.847 f/cm^3 right?
Found 2 solutions by mananth, Alan3354:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
mass = density *volume
volume = pi * r^2 l where r is radius
= 7.847 *3.14 *(1.25)^2*8 =308 grams

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
if a solid steel cylindrical rod is 8 cm in length and has a diameter of 2.5 cm and steel weigh 7.847 g/cm^3, how much does the rod weigh? round the answer to the nearest gram

i know 3.149(2.5^2)(8) is for the volume ... i think... then i would multiply that answer by the 7.847 f/cm^3 right?
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3.149 is not a good approximation for pi.
pi = 3.1415926535....
P = 22/7 is close and is often used.
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It's pi*r^2
You used d^2
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You're correct, multiply the volume by the density (with matching units) to find the weight.