Question

Zinc has a density of 0.258 lb/in³ (pounds per cubic inch).
Darius is making a pyramid out of solid zinc. The pyramid has a square base 6 inches on each side, and a height of 2.5 inches.
How many pounds of zinc does he need?
DO NOT ROUND FINAL ANSWER!!!

Answer 1

Why don’t you round the last answer

Answer 2

For this case, we have that by definition:

ρ = $\frac {M} {V}$

Where:

ro: Density

M: Mass

V: Volume

We find the volume of the pyramid:

$V = \frac {1} {3} * l ^ 2 * h$

Where:

$l ^ 2$: Represents the area of the base of the square pyramid

h: Represents the height

So:

$V = \frac {1} {3} * (6) ^ 2 * 2.5\\V = \frac {1} {3} * 36 * 2.5\\V = 30 \ in ^ 3$

We have to:

M = ρ* V

$M = 0.258 \frac {lb} {in ^ 3} * 30 \ in ^ 3\\M = 7.74 \ lb$

So, you need 7.74 pounds of zinc

Answer:

7.74 pounds