Proportions
Get a free home demo of LearnNext

Available for CBSE, ICSE and State Board syllabus.
Call our LearnNext Expert on 1800 419 1234 (tollfree)
OR submit details below for a call back

clear

Proportion
If the ratios between quantity A and quantity B is equal to the ratio between quantity C and quantity D, then the four quantities A, B, C and D, are said to be in proportion. Proportion is denoted by the signs '∷’ or ‘=’. 

Thus, the quantities 4, 16, 5 and 20 can be written as 4:16∷5:20 or 4:16 = 5:20.

The order of the terms in a proportion carries value. The quantities 4,16, 5 and 20 are in proportion, whereas 4, 20, 5 and 16 are not in proportion.

In the proportion a:b∷c:d, the quantities a and d are the extreme terms, and b and c are the middle terms.

Unitary method
The method of calculating the value of one unit and using this value to calculate the value of the required number of units is called the unitary method.

For example, suppose the cost of 8 bags is Rs 240. Now, to find the cost of 6 bags, using the unitary method, we first find out the cost of one bag. 

Cost of one bag = 240 8 = Rs 30

Now, the cost of 6 bags = 6 × 30 = Rs 180

Hence, the cost of 6 bags is Rs 180.

Summary

Proportion
If the ratios between quantity A and quantity B is equal to the ratio between quantity C and quantity D, then the four quantities A, B, C and D, are said to be in proportion. Proportion is denoted by the signs '∷’ or ‘=’. 

Thus, the quantities 4, 16, 5 and 20 can be written as 4:16∷5:20 or 4:16 = 5:20.

The order of the terms in a proportion carries value. The quantities 4,16, 5 and 20 are in proportion, whereas 4, 20, 5 and 16 are not in proportion.

In the proportion a:b∷c:d, the quantities a and d are the extreme terms, and b and c are the middle terms.

Unitary method
The method of calculating the value of one unit and using this value to calculate the value of the required number of units is called the unitary method.

For example, suppose the cost of 8 bags is Rs 240. Now, to find the cost of 6 bags, using the unitary method, we first find out the cost of one bag. 

Cost of one bag = 240 8 = Rs 30

Now, the cost of 6 bags = 6 × 30 = Rs 180

Hence, the cost of 6 bags is Rs 180.

Videos

References

Like NextGurukul? Also explore our advanced self-learning solution LearnNext
Offered for classes 6-12, LearnNext is a popular self-learning solution for students who strive for excellence
Explore
Animated Video
lessons
All India
Test Series
Interactive Video
Experiments
Best-in class
books

Join India's most happening

Educational community