Question

20 points and brainliest to the fastest, right answer!

Please answer ASAP: Use cross products to determine which of the following proportions are equivalent to each other.
Select all situations that apply.
a/b=c/d
a/c=b/d
a/d=c/b
b/a=d/c
d/a=c/b

Answer 1

(a+c)/(b+d) = (a-c) / (b-d)
cross multiply
ab -ad +bc -cd = ab +ad -bc -cd
cancelling ab and -cd, on both sides of eqn

combining like terms
-2ad = -2bc
dividing both sides by (-2)
ad =bc
dividing both sides by (bd)
a/b = c/d,,,,,,,,,as required

Answer 2

ad=cb
ad=cb
ab=cd
bc=da
bd=ac
1 and 2 are equal