Answer:
Step-by-step explanation:
1) 4 : 7 ? 12 : 21
If product of mean is equal to product of extremes, then they are proportion
Product of extremes = 4*21 = 84
Product of mean = 7 * 12 = 84
Product of extremes = Product of mean
They are in proportion
4 : 7 :: 12 : 21
2) 2 : 3 ? 3: 2
Product of extremes = 2*2 = 4
Product of mean = 3*3 = 9
Product of extremes ≠ Product of mean
They are not in proportion
2 : 3 ≠ 3 : 2
3) 3/4 ? 8/6
3 : 4 ? 8:6
Product of extremes = 3 * 6 = 18
Product of mean = 4 * 8 = 24
Product of extremes ≠ Product of mean
They are not in proportion
3 : 4 ≠ 8 : 6
4) 1/5 ? 5/25
1:5 ? 5 : 25
Product of extremes = 1 * 25 = 25
Product of mean = 5 * 5 = 25
Product of extremes = Product of mean
They are in proportion
1 : 5 :: 5 : 25