Solve Exercise 3 on Page 77 of the 5th Grade Math Textbook

Step-by-step Solution for Exercise 3 on Page 77 of the 5th Grade Math Textbook

Problem:
A rectangular piece of land with a length of 18m and a width of 15m. 20% of the land area is reserved for building a house. Calculate the area of the land reserved for building a house.

Solution Method:
- Calculate the area of the rectangular piece of land by multiplying the length by the width
- Calculate the area of the land reserved for building a house by multiplying the land area by 20% (divide by 100, then multiply by 20). 

Answer:
          The area of the land is:
                 18 x 15 = 270(m²)
         The area of the land reserved for building a house is:
                  270 : 100 x 20 = 54(m²)
                            The answer: 54m²

This is the solution for exercise 3 on page 77 of the 5th grade math textbook. Additionally, there are 3 other exercises: Solve Exercise 1 on Page 77 of the 5th Grade Math Textbook, Solve Exercise 2 on Page 77 of the 5th Grade Math Textbook, and Solve Exercise 4 on Page 77 of the 5th Grade Math Textbook. Let's see the guidance on Solving 5th grade math page 77 to study Math class 5 well