3. The base of parallelogram is 14cm, the height is 9cm, and the area is (); The area of a triangle with equal base and equal height is ().

5. There are a pile of steel pipes on the construction site, with trapezoidal cross section. It is known that there are 2 steel pipes on the top floor, 12 steel pipes on the bottom floor, and 1 1 steel pipes are stacked in * * *, and there are () steel pipes in this pile.

6. The area of a triangle is 30 square centimeters smaller than that of four parallel sides with the same height as its base, so the area of this triangle is ().

7. The area of a triangle is 4.5 square decimeters, the base is 5 decimeters, and the height is () decimeters.

8. The perimeter of an equilateral triangle is 18cm, the height is 3.6cm, and the area is () cm2.

Second, true or false questions (2 points for each question, *** 10)

1. Two triangles with the same area can be combined into a parallelogram. ()

2. The area of parallelogram is equal to twice the area of triangle. ()

3. Two identical trapezoids can form a parallelogram. ()

4. Extruding a rectangular frame into a parallelogram can reduce the area. ()

5. The areas of two triangles are equal, and the base and height must also be equal. ( )

Three, multiple-choice questions (2 points per question, ***8 points)

1. An equilateral triangle must be a _ _ _ _ _ triangle. []

A. acute angle; B. right angle; C. obtuse angle

2. Two identical acute triangles can be combined into a _ _ _ _ _ _ []

A. rectangle; B. square; C. parallelogram; D. trapezoid

3. Divide a parallelogram into two trapeziums at will, and the _ _ _ _ _ in these two trapeziums is always equal. []

A. high; B. area; C. Sum of upper and lower bottoms

Fill in the blanks.

1. When the calculation formula of parallelogram area is derived, the parallelogram can be transformed into () shape by cutting and complementary translation.

When deducing the calculation formula of triangle area, two identical triangles can be combined into a () shape to push it.

When deducing the formula of trapezoid area, two identical trapezoids can be combined into a () shape to deduce.

4. The two right sides of a right triangle are 3cm and 4cm respectively, and the area of this right triangle is () cm2.

7. The length of the bottom of the triangle is expanded by 2 times, and the height remains unchanged. The area of the extended triangle is larger than that of the original triangle ()

Time magazine.

Third, judge the question.

1. The area of the parallelogram is equal to the area of the rectangle. ( )

2. A triangle with equal base and equal height can be made into a parallelogram. ( )

As long as we know the length and height of the sum of the two bottoms of a trapezoid, we can find its area. ( )

5. The areas of two equilateral triangles with equal perimeters must be equal. ( )

Fill in the blanks.

1. The area of a triangle is 25 square centimeters, and the area of a parallelogram with equal base and equal height is

() square centimeters.

2. The parallelogram has a base length of 16m, a height of 12m and an area of () m2.

Draw a new triangle in a rectangle with a length of 9 cm and a circumference of 26 cm. The area of this triangle is () square centimeters.

4. The base of the triangle is expanded by 3 times, the height by 2 times and the area by () times.

The height of triangle is equal to the height of trapezoid, and their areas are equal. The sum of the upper and lower base of the trapezoid is equal to the length of the triangle ().

6. The shaded area on the right is 15 cm2, which is rectangular.

The area is () square centimeters.

7. The base of a parallelogram is 6 cm, its height is 14 cm, its area is () square cm, and the area of a triangle with the same height as its base is () square cm.

8. As shown in the figure, the side length of each square is 1 cm, and the area of this small fish is () square cm.

9. There is a rectangle with a length of 15cm and a width of 8cm, and there is a right-angled trapezoid with an upper bottom of 7cm, a lower bottom of 6cm and a height of 8cm. They are combined into a trapezoid whose area is () square centimeters.

10. The base length of the parallelogram is 10 decimeter and the height is 4 decimeter. If the base number remains unchanged, the height will be increased by 2 decimeters, and the area will be increased by () square decimeters; If the height remains the same and the bottom is increased by 2 decimeters, the area will increase by () square decimeters.

1 1. Draw a rectangle made of wood strips into a parallelogram (as shown in the figure). Originally, the area of rectangle was () square centimeter, now the area of parallelogram is () square centimeter, and now the perimeter of parallelogram is () centimeter.

Second, judge.

1. The area of trapezoid is smaller than that of parallelogram. ( )

2. The upper bottom of the trapezoid must be shorter than the lower bottom. ( ):

3. The heights of two triangles are equal, but the areas are not necessarily equal. ( )

4. Any two triangles can be combined into a parallelogram. ( )

5. Divide a parallelogram into two triangles, which must be exactly the same. ( )

6. Two identical right-angled trapezoids can form a rectangle. ( )

7. Rectangles with equal perimeters and parallelograms have equal areas. ( ):

8. The areas of two parallelograms with equal base and equal height are equal. ( );

9. Divide a parallelogram into two identical trapeziums, and the heights of the two trapeziums must be equal. ( ):

Third, choose carefully.

1. The base of the parallelogram is reduced 10 times, and the height is enlarged 10 times. The area of this parallelogram is ().

A. the size is equal to the original B. it is reduced by 10 times, and C. it is expanded by 10 times.

2. Draw a rectangle as a parallelogram (the length of four sides is constant), and its area is ().

A. smaller than the original B. larger than the original C. equal to the original

3. Two identical right triangles cannot be combined into one ().

A. Trapezoidal square triangle

4. This trapezoid is () high.

A. Countless B.2 C. 1

5. Circle three equal-length iron wires into rectangles, squares and parallelograms respectively to form the area of the figure ().

A. square is big B. rectangle is big C. parallelogram is big

Draw a new triangle in a parallelogram with an area of 42 square meters. The area of this triangle is ().

2 1

Fifth, solve the problem.

2. A pile of wood is neatly stacked on the ground, with the bottom layer 25, the top layer 6 and the top layer 20. Each lower layer has one more than the previous one. How many sticks are there in this pile of wood?

3. Cut a trapezoidal paper with a bottom of 24 cm, an upper bottom of 18 cm and a height of 14 cm into triangular paper as large as possible, and find the total area of the remaining paper.

7. Cut a rectangular piece of paper with a length of 12 decimeter and a width of 4 decimeters into an isosceles triangle with a right angle of 4 decimeters. * * * How many pieces can you cut?

(1), the area of the triangle is equal to the base times the height. ( )

(2) Two triangles can be combined into a parallelogram. ( )

(3) The triangle has an area of 24 square meters, a height of 8 meters and a bottom of 3 meters.

( )

(4) A parallelogram composed of two identical triangles, whose base and height are equal to the base and height of the triangle respectively. ( )

(5) The area of a triangle is half that of a parallelogram. ( )

(6) The height of a triangle is 4 cm, the bottom is 5 cm, and the area is

4×5÷2= 10 (cm). ( )

Unit Exercise of "Graphic Area (1)"

fill (up) a vacancy

(1) A parallelogram with a base of 5.7 meters, an area of 26.22 square meters and a height of () meters.

(2) Triangle and parallelogram are equal in base and height. If the area of the parallelogram is 128 square meters, then the area of the triangle is ().

(3) The trapezoid with an upper bottom of 3.4 cm, a lower bottom of 4.8 cm and a height of 2.7 cm has an area of ().

(4) The base of the parallelogram is 2.4 decimeters, the height is half of the base, and the area is ().

(5) The base of the triangle is 0.4m, twice as high, and its area is ().

(6) The perimeter of a square is16cm, and the area is () cm2.

(7) The upper bottom of the trapezoid is 4.5 cm, the lower bottom is 5.2 cm, the height is 5 cm, and its area is () square cm.

(8) Trapezoidal, with an area of 6.3 square meters, the upper bottom 1.4 meters, the height 1.2 meters and the lower bottom () meters.

Second, judgment (draw "√" on the right and "×" on the wrong)

(1) The parallelogram has only one height. ( )

(2) Two triangles with equal areas can be combined into a parallelogram. ( )

(3) Triangles with equal bases and equal heights must have equal areas. ( )

(4) The area of parallelogram must be greater than that of triangle. ()a

(5) The right picture shows the height of triangle A made by Beibei. ()h

Third, choose

(1) After the parallelogram is cut and repaired into a rectangle, the area remains unchanged and the perimeter ().

A. expand B. shrink C. unchanged

(2) The CD at the top and bottom of the trapezoid is constantly changing. When the length of CD is equal to zero, D C

This picture becomes (); When CD is as long as AB, this graph

The shape becomes (). A b

A. triangle b rectangle c parallelogram

(3) A parallelogram with an area of 56 square decimeters, a base of 14 decimeter and a height of ().

4 decimetres, 2 decimetres, C.8 decimetres.

(4) The area indicated by letters in the shaded area in the figure is ().

A. ah b ah+ah c ah

(5) A parallelogram with the same base, three times higher and an area of ().

A. Zoom in 3 times B. Zoom in 9 times C. Zoom out 3 times.

(6) Let the triangle have an area of 63 square decimeters, a height of 7 decimeters and a base of ().

A.4.5 B. 18

(7) Divide a parallelogram into two trapeziums at will, and the () in these two trapeziums is always equal.

A. Height B. Area C. Sum of upper and lower bottoms

(8) A triangle with five times the height of the same base has an area of ().

A. Zoom in 5 times B. Zoom in 25 times C. Zoom out 25 times

(9) Two trapezoids of () can be combined into a parallelogram.

A. equal area B. equal circumference C. isosceles trapezoid D. exactly the same

Fourth, super change.

Bottom (cm) Height (cm) Area (cm 2)

Rectangular 8 6.5

Parallelogram 7.5 60

4.3 25.8

Triangle 10.2 5.8

24 150

Ladder up 4.2 down 6.7 54.5

5. Hands-on: Measure relevant data and calculate the area.

Sixth, the smart club

1. Triangle nursery with a bottom length of 80m and a height of 35m. Chrysanthemum seedlings are planted in the nursery, and each chrysanthemum seedling covers an area of 0.2m2 How many chrysanthemum seedlings do you need in this garden?

2. As shown in the figure, a trapezoidal fence surrounded by a wall is 40 meters long. How many square meters is its area?