Solving Exercise 4 Page 47 Math 5 Textbook

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Ngày cập nhật gần nhất: 15/4/2026

Solving exercise 4 on page 47 of Math 5 Textbook in Focus Practice, calculating playground area with measurement units in square meters, hectares.

Solution guide for exercise 4 on page 47 of Math 5 Textbook

Problem:
A rectangular playground has a half-perimeter of 0.15km and the width is 2/3 of the length. Calculate the area of the playground with measurement units in square meters, hectares.

To solve this problem, first convert the given perimeter from kilometers to meters. Then, draw a diagram representing the rectangular field and find the total number of equal parts. Next, determine the width (smaller number) by dividing the total by the number of equal parts and multiply by the number of parts for the smaller dimension. After that, find the length (larger number) by subtracting the width from half of the perimeter. Finally, calculate the area of the field by multiplying the length and width obtained earlier. Convert the result to square meters and hectares for the final answer.

The solution is as follows:

Convert 0.15 km to 150 m. Now, observe the diagram:

According to the diagram, the total number of equal parts is:

The sum of 2 and 3 equals 5 (parts)

The width of the field is:

Divide 150 by 5 and multiply by 2 to get 60 (meters)

The length of the field is:

The area of the field is:

Calculate the area by multiplying 90 by 60 to get 5400 (m²)

Convert: 5400m² = 0.54 ha