Answer

Verified

414k+ views

**Hint:**A proportion is a mathematical comparison between two numbers. Often, these numbers can represent a comparison between things or people. For example, say you walked into a room full of people. You want to know how many boys there are in comparison to how many girls there are in the room. You would write that comparison in the form of a proportion.

A ratio is a way to compare two quantities by using division as in miles per hour.

A proportion on the other hand is an equation that says that two ratio are equivalent

If one number in a proportion is unknown you can find that number by solving the proportion

It is formulate as:

\[a:b::c:d\]

\[ \Rightarrow \dfrac{a}{b} = \dfrac{c}{d}\]

\[ \Rightarrow a \times d = b \times c\]

Therefore,

**Complete step by step answer:**

Given

\[5:15 = 4:x......(1)\]

We need to find the value of \[x\]in proportion.

We know that if two number are in proportion i.e \[a:b::c:d\] or \[a:b = c:d,\]then we can write them as\[\dfrac{a}{b} = \dfrac{c}{d}\]

Hence \[(1) \Rightarrow \dfrac{5}{{15}} = \dfrac{4}{x}\]

Cross multiplying, we get

\[5 \times x = 15 \times 4\]

\[ \Rightarrow x = \dfrac{{15 \times 4}}{5}\]

As 5 was in multiplication LHS it will be in division on RHS

\[ \Rightarrow x = 3 \times 4\]

\[ \Rightarrow x = 12\]

Hence the value of \[x\] is 12.

**Note:**For four numbers a, b, c, d if \[a:b = c:d\] then \[b:a = d:c,\] it is known as invert and properly

For four numbers a ,b, c, d if \[a:b = c:d\] then \[a:c = b:d\]if the second and third terms interchange their places, it is known as alternator property.

We can also use component do and dividend property to simply the proportion problems.

Recently Updated Pages

Identify the type of clause underlined in the sentence class 8 english CBSE

Which statement describes the density of the inner class 8 social science CBSE

Babur considered which ruler of Gujarat as among the class 8 social science CBSE

Which island groups were affected by the Tsunami in class 8 social science CBSE

Which is the administrative system that works under class 8 social science CBSE

The year in which the state was named as Karnataka class 8 social science CBSE

Trending doubts

Difference Between Plant Cell and Animal Cell

Give 10 examples for herbs , shrubs , climbers , creepers

Fill the blanks with the suitable prepositions 1 The class 9 english CBSE

Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE

Write a letter to the principal requesting him to grant class 10 english CBSE

Change the following sentences into negative and interrogative class 10 english CBSE

Write the 6 fundamental rights of India and explain in detail

Name 10 Living and Non living things class 9 biology CBSE

The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths