All questions of Measuring Length for Class 4 Exam

Measuring tape is flexible and useful for measuring clothes or curved surfaces.

Understanding Length Measurements
To determine which length is the smallest among the given options, we need to convert all measurements to the same unit for easy comparison. The options are:
- 1 meter
- 75 centimeters
- 90 centimeters
- 1/2 meter
Conversion to Centimeters
1 meter is equivalent to 100 centimeters. Therefore, we can convert the other measurements as follows:
- 1 meter = 100 centimeters
- 75 centimeters = 75 centimeters (no conversion needed)
- 90 centimeters = 90 centimeters (no conversion needed)
- 1/2 meter = 0.5 meter = 50 centimeters (since 1 meter = 100 centimeters, half of that is 50)
Comparing the Lengths
Now, we can compare all the lengths measured in centimeters:
- 1 meter = 100 centimeters
- 75 centimeters = 75 centimeters
- 90 centimeters = 90 centimeters
- 1/2 meter = 50 centimeters
Identifying the Smallest Length
Now, we can easily identify the smallest length from the converted values:
- 100 cm (1 meter)
- 75 cm (75 centimeters)
- 90 cm (90 centimeters)
- 50 cm (1/2 meter)
Among these, 50 centimeters is the smallest. Therefore, the correct answer is option D: 1/2 meter.
This conversion and comparison method helps clarify which lengths are smaller and makes it easier to understand how different units relate to one another.

Understanding the Correct Unit for Measuring Book Thickness
When measuring the thickness of a book, it is essential to choose the appropriate unit of measurement. Let’s break down the options provided:
Unit Options
- Meter (a): This unit is quite large and is typically used for measuring longer distances. For example, a meter is about the height of a kitchen counter, making it unsuitable for measuring the thickness of a book.
- Kilometer (b): This unit is even larger than a meter and is used primarily for measuring long distances, such as the distance between cities. Therefore, it is not appropriate for a book’s thickness either.
- Centimeter (c): This unit is part of the metric system and is commonly used for measuring smaller lengths. A book’s thickness generally ranges from a few centimeters to several centimeters, making this the most suitable unit for this purpose.
- Milliliter (d): This unit measures volume, not length. It is typically used for liquids and would not apply to a book’s thickness.
Conclusion
The correct choice for measuring the thickness of a book is Centimeter (c). This unit provides a precise and practical way to express the thickness, which is essential for understanding the book's physical dimensions when storing or shelving it. Using centimeters allows for easy comparison and is standard in most contexts related to books and printed materials.

Understanding the Comparison of Lengths
When comparing lengths, it's essential to understand the basic concept of measurement. In this case, we are comparing two lengths: 90 cm and 120 cm.
Identifying the Values
- 90 cm: This is the shorter length.
- 120 cm: This is the longer length.
Comparison Explanation
To determine the relationship between these two lengths, we can analyze their values:
- 90 cm is less than 120 cm: This means that if you were to measure an object that is 90 cm long and another that is 120 cm long, the second object would be longer.
Using Comparison Symbols
In mathematical terms, we use symbols to show the relationship:
- 90 cm < 120="" />:="" the="" symbol=""><" indicates="" that="" 90="" cm="" is="" less="" than="" 120="" cm.="">Conclusion
Thus, the correct answer to the comparison of 90 cm and 120 cm is option 'B':
- 90 cm < 120="" />
This indicates that 90 cm is indeed shorter than 120 cm, confirming that option 'B' is the correct choice. Understanding such comparisons helps in grasping basic mathematical concepts and measurements. 120="" cm="" this="" indicates="" that="" 90="" cm="" is="" indeed="" shorter="" than="" 120="" cm,="" confirming="" that="" option="" 'b'="" is="" the="" correct="" choice.="" understanding="" such="" comparisons="" helps="" in="" grasping="" basic="" mathematical="" concepts="" and="">
This indicates that 90 cm is indeed shorter than 120 cm, confirming that option 'B' is the correct choice. Understanding such comparisons helps in grasping basic mathematical concepts and measurements.>

Height measures how tall something is — from bottom to top.

1/4 meter = 25 centimeters.

3 meters = 300 cm. 300 ÷ 30 = 10 notebooks.

The meter is a standard unit for measuring long distances, such as the height of a door or the length of a room.

To compare lengths accurately, both objects must be measured using the same unit.