Question

what number must be added to each of the following number 39, 42, 9 and 10 to get the number which are in proportion​

Answer 1

Answer:

6

Step-by-step explanation:

for numbers to be in proportion,

The product of means must be equal to the product of extremes i.e.,

a:b::c:d

a*d=b*c

in this problem:

39+x:42+x::9+x:10+x

So...

(39+x)*(10+x)=(42+x)*(9+x)

390+10x+39x+$x^{2}$=378+9x+42x+$x^{2}$

390+49x=378+51x

2x=390-378

2x=12

x=6

Therefore, 6 must be added to each of the numbers for them to be in proportion.

HOPE IT HELPS!!!!