Use cross products to determine which of the following pairs of ratios cannot form a proportion?
A-1/3 X 3/9
B-2/3X 4/9 ********
C- 2/3 X 4/6
D- 1/3 X 2/6
Am I correct?
Yes, you're right.
To determine which pairs of ratios cannot form a proportion, we can use the cross product method.
To find the cross product of a pair of ratios, we multiply the numerator of the first ratio by the denominator of the second ratio, and then multiply the denominator of the first ratio by the numerator of the second ratio. If the two cross products are not equal, then the pair of ratios does not form a proportion.
Let's apply this method to each pair of ratios:
A-1/3 X 3/9
Cross product: (1 * 9) = (3 * 3)
Cross product: 9 = 9
Since the cross products are equal, the pair of ratios (1/3 and 3/9) forms a proportion.
B-2/3 X 4/9
Cross product: (2 * 9) ≠ (3 * 4)
Cross product: 18 ≠ 12
Since the cross products are not equal, the pair of ratios (2/3 and 4/9) does not form a proportion. So, you are correct about B.
C-2/3 X 4/6
Cross product: (2 * 6) = (3 * 4)
Cross product: 12 = 12
Since the cross products are equal, the pair of ratios (2/3 and 4/6) forms a proportion.
D-1/3 X 2/6
Cross product: (1 * 6) ≠ (3 * 2)
Cross product: 6 ≠ 6
Since the cross products are not equal, the pair of ratios (1/3 and 2/6) does not form a proportion.
So, the correct answer is B - 2/3 X 4/9.