Question

WILL MEDAL+FAN!!!
how do i cross multiply?
PLEASE DO NOOOOT give me the answer. I would like to learn it :)
13/x = 39/87

(thirtyteen over 'X')(thirtynine over eightyseven)

Answer 1

yes

Answer 2

"cross multiply" as the math teachers say

Answer 3

i dont know how to cross multiply, i forgot how :(

Answer 4

\[\frac{a}{b}=\frac{c}{d}\\
a\times d = b\times c\]

Answer 5

\[39\times x=87\times 13\]

Answer 6

then \[x=\frac{87\times 13}{39}\]

Answer 7

i dont understand that ?