it costs a family $324 to buy a 10 ft by 12 ft rug. at this rate what will it cost them to buy a 15 ft by 18 ft rug?
i divided 10 and 12 by 2 to get 5 and 6. i divided 15 and 18 by 3 and got 5 and 6. what do i do next?
hmm i don't know if that'll work.
what i would do is set up a proportion.
the fractions would be area to price.
$\displaystyle \frac{120}{324}=\frac{270}{x}$
See how I got that?
Criss-Cross multiply: $\displaystyle 87480 = 120x \Rightarrow x = 729$
So the price would be $729.