Think about the proportion and the cross products for this problem: Shelley sold one customer 5 peanut butter biscuits for $3. She sold another customer 7 beef treats for $4.20.
Because the cross products are equal, which statements are true? Select all that apply.
The ratios are not equivalent.
The ratios are equivalent.
The ratios are not a proportion.
The ratios are a proportion.

When cross products are equal, they will have the same ratio. You can prove this by cross multiplying the fractions:

5|3 = 7|4.20

Cross multiply the two:

21=21

This proves that the ratios are equivalent.

The ratios are equivalent.

The are a proportion.

Explanation:

Hope this helps.

687.09 dollars       happy now

step-by-step explanation: 6870

1857 times .63 equals 1169.91 subtract that from 1857 you get 687.09

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this