Join 60,000+ competitive exam aspirants
The mean proportional of 25 and 36 is:
36
60
25
30
30
The mean proportional of two numbers a and b is simply the geometric mean, which is the square root of their product. Here, 25├Ч36тАЛ=25тАЛ├Ч36тАЛ=5├Ч6=30.
Two numbers are 25 and 36.
x=a├ЧbтАЛ
The mean proportional of two numbers a and b is simply the geometric mean, which is the square root of their product. Here, 25├Ч36тАЛ=25тАЛ├Ч36тАЛ=5├Ч6=30.
Students often mistake 'mean proportional' for 'arithmetic mean' (average) and incorrectly calculate (25+36)/2=30.5.
Define the formula
The mean proportional x of two numbers a and b is given by the square root of their product.
x=a├ЧbтАЛ
Substitute the values
Given a=25 and b=36, substitute these into the formula.
x=25├Ч36тАЛ
Calculate the square root
Calculate the product or separate the square roots: 25тАЛ├Ч36тАЛ=5├Ч6.
x=5├Ч6=30
D is correct because the square root of the product of 25 and 36 is 900тАЛ, which equals 30.
This concept is foundational for understanding similar triangles and the geometric mean theorem in Euclidean geometry.