Question

If a 2.5 g sample of gold is hammered into an equilateral triangle .28mm thick, how long are the sides?

Answer 1

Could you help me? @phi

Answer 2

I think I know how to do it, but I would like some assistance if possible! @phi

Answer 3

what is the density of gold ?

Answer 4

is it 19.3?

Answer 5

I don't know, but you should look it up and post it here. and be sure to add the units

Answer 6

It is 19.3

Answer 7

I just looked it up, bur I don't know how it would be that.

Answer 8

and what are the units ? any idea ?

Answer 9

I think the final units must be in cm^3 or g/cm^3

Answer 10

ok, so we can write a ratio
\[ \frac{19.3 \ g}{1 \ cm^3}= \frac{2.5 \ g }{x} \]

Answer 11

is this using the factor-label method?

Answer 12

can you find the value for x?
I would first flip both sides, and write the ratio as
\[ \frac{1 \ cm^3}{19.3 \ g}= \frac{x}{2.5 \ g } \]

Answer 13

I would then multiply both sides by 2.5 g
\[ x = \frac{2.5}{19.3}\ cm^3\]

Answer 14

Would it be .1295?

Answer 15

Because that's what I did, but then after I did that I got confused

Answer 16

yes, but you should always include the units
x= 0.12953 cm^3

you have that many cubic cm of gold

now we need the volume of an equilateral shape
any idea on the formula for its volume ?

Answer 17

I would use area of the base * height
what is the area of an equilateral triangle? (there is a formula where all you need is the length of one side)

Answer 18

I thought that the .1295 was the volume? It isn't?

Answer 19

it is the volume of the gold
and when you pound it into the shape of a triangle, the triangle will have the same volume