Question

Are 13, 39, 7, 21 in proportion?

Answer 1

Answer:

yes

they are in proportion

Step-by-step explanation:

13:39::7:21

1:3::1:3

Answer 2

13, 39, 7, 21​​ are in proportion.

Step-by-step explanation:

We have,

13 : 39 : : 7 : 21

To find, 13, 39, 7, 21​ are in proportion or not.

∴ 13 : 39 : : 7 : 21

Here, a = 13, b = 39, c = 7 and d =21

We know that,

Product of means = Product of extremes

⇒ b × c = a × d

∴ b × c =  39 × 7  = 273 and

a × d = 13 × 21  = 273

∴ Product of means = Product of extremes = 273

Thus, 13, 39, 7, 21​​ are in proportion.