Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Find the fourth proportional of 15, 25 and 12.
20
30
15
25
20
Use the property of proportionality: the product of the means equals the product of the extremes. Here, 15├Чx=25├Ч12, so x=(25├Ч12)/15.
Three numbers: 15, 25, and 12.
x=ab├ЧcтАЛ
Use the property of proportionality: the product of the means equals the product of the extremes. Here, 15├Чx=25├Ч12, so x=(25├Ч12)/15.
Confusing the order of terms. For four numbers a, b, c, and d in proportion, a/b=c/d, so d=(b├Чc)/a.
Define the Proportion
Let the fourth proportional be x. By definition, the ratio of the first two numbers is equal to the ratio of the last two numbers: 15:25=12:x.
15:25::12:x
Set up the equation
Using the properties of proportions, the product of the means is equal to the product of the extremes: 15├Чx=25├Ч12.
x=1525├Ч12тАЛ
Calculate the result
Simplify the expression: x=15300тАЛ=20.
x=20
A is correct because the fourth proportional of 15, 25, and 12 is calculated as (25├Ч12)/15=20.
This concept is fundamental to solving problems in partnerships, mixture and alligation, and scale drawing in geometry.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants