Tổng hợp các dạng toán về hình chữ nhật lớp 5 từ cơ bản đến nâng cao

In the 5th grade math program, they will learn knowledge related to rectangles. Along with that, the types of mathematics of 5th grade rectangles are also quite diverse, requiring students to understand each method of solving to conquer the most effective exercise. So, in the following content, Mầm non Cát Linh will synthesize and analyze in detail for everyone to refer.

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Knowledge to remember when solving grade 5 rectangular math

Basically, in terms of knowledge of grade 5, rectangles will inherit the knowledge you have learned from grade 3 and 4th grade but will be more advanced. Specifically:

What is a rectangle concept?

The rectangle is known as a special quadrilateral with 4 right angles, or it is a parallelogram with a right angle.

Signs of rectangle

• The quadrilateral with three right angles is rectangular.

• The trapezoid has a rectangular angle.

• The parallelogram has a right angle of rectangle.

• The parallelogram has two equal diagonal lines.

The formula for calculating the circumference of the rectangle

The perimeter of the rectangle is calculated by 2 times of the sum of the length and width: C = 2 x (A+B).

The formula for calculating the area of ​​the rectangle

The rectangular area will be equal to the product of 2 adjacent edges. S = axb

Maths of grade 5 rectangles and solutions

For the 5th grade mathematical forms of rectangles are mainly basic knowledge, not too advanced for students to grasp the exam preparation support and create a premise to learn more advanced knowledge. Specifically:

Form 1: Identify rectangles

Solution: They will need to understand the concept, as well as the signs of the rectangle learned to be able to give accurate answers.

For example, how many rectangles in the following picture are in the following picture?

Prize:

Figure A has 2 rectangles

Figure B has 1 rectangle

Figure C has 3 rectangles

Form 2: Calculate the area of ​​the rectangle

Solution: They need to memorize the formula for calculating the rectangular area to solve the exact exercise.

For example: Calculate the area of ​​the rectangle, know 3 times the length of the width and the width of 24cm.

Solution instructions:

The rectangular width is:

24: (3 – 1) = 12 (cm)

The rectangular length is:

24: (3 – 1) x 3 = 36 (cm)

The rectangular area is:

36 x 12 = 432 (cm2)

Answer: 432 cm2

Form 3: Calculate the circumference of the rectangle

Solution: Students also apply the formula for calculating the most typical circumference equal to the length plus the width (the same unit of measurement) and then multiply with 2.

For example: Calculate the circumference of the rectangle, know the length of the width of 5m and equal to 5/4 width.

Instructions for solving

The rectangular width is:

5: (5 – 4) x 4 = 20 (m)

The rectangular length is:

5: (5 – 4) x 5 = 25 (m)

The circumference of the rectangle is:

(20 + 25) x 2 = 90 (m)

Answer: 90 m

Summary of exercises on the 5th grade mathematical math

After grasping the type of mathematics of grade 5 and the solution for each form, Mầm non Cát Linh will summarize some exercises for them to practice.

I – Topic:

Lesson 1: A rectangle has a length of a half width and circumference of 180m. Ask after the length of 5m, how many meters must be pulled in the length to get a square?

Lesson 2: A rectangle is 3 times the width. Pulling an additional 18m length, a width of 24m is a square. Find the original size of the rectangle.

Lesson 3: Rectangular width is 1/3 of the length. If the length goes 72m, the width is reduced by 8m, the new rectangle has a length of half the width and the circumference is 160m. Calculate the original rectangular circumference.

Lesson 4: On a square table, a flowerpot is placed so square that one side of the flowerpot coincides with an edge of the table in the middle of that table (as shown). The shortest distance from the table to the bottom of the flowerpot is 35cm, knowing the remaining area of ​​the table is 63dm2. Calculate the edge of the table surface.

Lesson 5: Indicates the square ABCD has a circumference of 24cm. M, n, p, q are the midpoints of the square edges. Calculate the area of ​​the cross -brick part in the picture on the side.

Lesson 6: Give the square with a 4cm long edge. In the following statements, which statement is right?

A. The square area is equal to the square circumference.

B. Large square square area.

C. The square circumference is smaller than the square area

D. All three sentences on the wrong answer

Lesson 7: Let the square ABCD know AM = MB = BN = NC = CE = ED = DF = Fa = 1cm (Figure). Calculate the area of ​​the cross brick.

Lesson 8: Give 1dm square, connecting the four -sided midpoint to form the second square. Again connecting the fourth -sided midpoint of the second square to form the third square, just like that to the tenth square. Calculate the total area of ​​those 10 squares.

Lesson 9: The square ABCD has an edge of 8cm, AC cuts BD at O. Draw the center circle O O OA radius as shown. Calculate the area of ​​the cross brick.

Lesson 10: Given a rectangle ABCD with an area of ​​48cm2; MC = md; BN = 2/3BC. Calculate the area of ​​the triangle AMN.

Lesson 11: A rectangle has a perimeter of 60m. Calculating its area, knowing that between the width of that rectangle and increasing the length to 2m, we get a new rectangle with an area of ​​24 square meters.

Lesson 12: A rectangle has a width length. If each direction increases by 1 m, the new rectangle has an area of ​​26 square meters. Calculate the original rectangular circumference.

Lesson 13: A square yard of the circumference of 20 m, people expand to the right 2m and expand the left 1 m. Ask after expanding the circumference of the yard?

Lesson 14: A rectangle is three times the width and has an area of ​​75 cm2. Calculate the circumference of that rectangle?

Lesson 15: Give a square with a circumference of 96 cm. Divide that square into two rectangular shapes with two circumference equal to 12 cm. Calculate the circumference of each rectangle.

Lesson 16: A rectangle has a circumference of 70 cm, divided into two parts by a line parallel to the width so that the first part is a square, the second is a rectangle with a length of 3 times the width. Find the original rectangular area?

Lesson 17: There are many rectangles in the following drawing:

Lesson 18: Name the rectangular objects close to you.

Lesson 19: Find the wrong sentence in the following sentences

A. In the rectangle there are two equal diagonal lines.

B. In the rectangle there are two diagonal intersects at the midpoint of each line.

C. In the rectangle there are two adjacent edges.

D. In the rectangle, the intersection of the two diagonal lines is the center of that rectangle

Lesson 20: The following signs, which signs are not correct?

A. The parallelogram has two diagonal lines intersecting at the midpoint of each line are rectangles.

B. The quadrilateral has three square angles that are rectangles.

C. The scale trapezoid has a rectangular angle.

D. The parallelogram has two equal diagonal lines, which are rectangles.

II: Answers

Lesson 1: Answer: 23m

Lesson 2: Answer: Length 9m, width: 3m

Lesson 3: We have:

Half of the new rectangular circumference is: 160: 2 = 80 (m)

The new width is: [80 : (2 x 3)] x 2 = 32 (m)

The new length is: 80 – 32 = 48 (m)

The initial width is: 32 + 8 = 40 (m)

The initial length is: 48 + 72 = 120 (m)

The original rectangular circumference is: (120 + 40) x 2 = 320 (m) Answer: 320m

Lesson 4:

Suggest:

We can transfer the vase to the corner of the table

Fb = 35 x 2 = 70 (cm)

S3 = 70 x 70 = 4900 (cm2) = 49 (dm2)

S1 = S2 = (63 – 49): 2 = 7 (dm2) = 700 (cm2)

The edge of the flowerpot is: 700: 70 = 10 (cm)

The side of the table is: 70 + 10 = 80 (cm) Answer: 80 cm

Lesson 5: The edge of the square ABCD is:

24: 4 = 6 (cm)

The total area of ​​Figure 1, Figure 2, 3, Figure 4 is equal to the area of ​​a circle with a radius:

6: 2 = 3 (cm)

The total area of ​​Figure 1; Figure 2; Figure 3; Figure 4 is:

3 x 3 x 3.14 = 28.26 (cm2)

The square area ABCD is:

6 x 6 = 36 (cm2)

The area of ​​the cross brick is:

36 – 28.26 = 7.74 (cm2)

Answer: 7.74 (cm2)

Lesson 6: A. The square area is equal to the square circumference.

Lesson 7: Answer: 4/5 cm2

Lesson 8: Answer: 1 511/512 dm2

Lesson 9: 36.48 m2

Lesson 10: Answer: 16 cm2

Lesson 11: Call the rectangular length A, the rectangular width is B, the old rectangular area is S1, the new rectangle is S2.

The total length and width of the old rectangle are:

A + B = 60: 2 = 30 (m)

Maintaining the width of the rectangle and increasing the length to 2m, the rectangular area increases by 24m2. So:

S1 = (a + 2) xb = s2 + 24 = axb + 24

Axb + 2 xb = axb + 24

2 xb = 24

b = 12 (m)

A = 30 – 12 = 18 (m)

So the original rectangular area is:

18 x 12 = 216 (m2)

Answer: 216 m2

Lesson 12: Answer: 50m

Lesson 13: Answer: 26m

Lesson 14: Answer: 40cm

Lesson 15: Answer: 42 cm and 54 cm

Lesson 16: Answer: 375 cm2

Lesson 17: Answer: 6 rectangles

Lesson 18: Painting frame, bookshelf, cabinet shelf, ruler, mirror …

Lesson 19: C

Lesson 20: A

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The secret to conquering the mathematical forms of grade 5 rectangles effectively

In order to support the baby to conquer the 5th grade math exercises about the effective rectangle, here are some secrets that parents, as well as children can apply:

• Make sure the theory: To conquer the exercise, parents need to regularly check whether the baby has remembered and grasped the knowledge of the rectangle or not from the concept, nature, signs of awareness, formula … If the child forgot, supplement and instruct in time is essential.

• Application of math learning in practice: In order for children to easily visualize rectangular knowledge, parents should give examples close to children, ask related questions such as listing 5 rectangular objects they see indoors, for the size of the assumption and asking the baby to calculate …

• Practicing and practicing regularly: Parents should often encourage and ask their children to do homework, practice regularly to avoid forgetting their knowledge. In addition to doing class exercises, parents can find more lessons on the Internet with their children to improve math skills.

• Make sure geometric knowledge with Mầm non Cát Linh Math: This is a bilingual math teaching application for preschool and elementary children. In the lesson content, it will stick to more than 60 math themes, including geometry, combined with video learning methods and interactive games will help children have better interest and remember knowledge. At the same time, the features that Mầm non Cát Linh Math develops will help improve your baby’s mathematical thinking capacity better. Parents can refer to the following video to better understand the application.

https://www.youtube.com/watch?v=7dsjpvhfros

Conclude

Above is the information sharing knowledge about mathematical types of 5th grade rectangles for parents, as well as students to refer. This is a math subject that will be available in most exam questions, as well as when studying classes higher. Therefore, parents can guide and teach to support the learning of the baby to achieve better results.

Nguồn: https://mncatlinhdd.edu.vn/ Tác giả: Nguyễn Lân dũng