Question

what number must be added to each of the number 5, 9, 7, 12 to get the numbers which are in proportion​

Answer 1

Answer:

here your answer....

3

Step-by-step explanation:

let the number be x

then the numbers will be

5+x,9+x,7+x,12+x

according to proportion

5+x:9x+7::7+x:12+x

= (5+x)/(9+x) = (7+x)/(12+x)

=(5+x)(12+x) = (9+x)(7+x)            

  Do cross multiplication

=(60+5x+12x+x square) = (63+9x+7x+x square)

=(60+17x+x square) = (63+16x+x square)

= 60+17x+x square = 63+16x+x square                           ( x square and x square gets cancelled )

= 60+17x = 63+16x

= 17x - 16x = 63 - 60

= x = 3                  Substitution  The numbers are: 5+x , 9+x , 7+x and 12+x

5+3 , 9+3 , 7+3 , 12+3

8:12::10:15

Product of extremes = Product of means

8*15 = 12*10

120 = 120

3 should be added to each of the numbers 5 , 9 , 7 and 12 to get the numbers which are in proportion

Answer 2

Answer:

3

Step-by-step explanation:

Let x be added to 5,9,17,27 to make them proportional

(5+x):(9+x)=(17+x):(27+x)

Product of mean=Product of extreme

(17+x)(9+x)=(5+x)(27+x)

153+17x+9x+x

2

=135+5x+27x+x

2

153+26x=135+32x

32x−26x=153−135

6x=18

x=3