Question

115 In a proportion, the second third and fourth terms are 7,35 and 49 respectively. Find the first term​

Answer 1

Concept:

Let 4 terms abcd be in proportion

a:b=c:d

so a and d are the extremes

and b and c are the means

the formula is product of means=product of extremes

ad=bc

Formula:

Product of means=Product of extremes

Solution:

Let the first term=x

so x and 49 are extremes and 35 and 7 are means.

x:7=35:49

so 49x=35x7

49x=245

x=245/49

x=5

so the first term is 5

Answer:

5