Test results of school grade name

I. Fill in the blanks (24 points)

1. When the compasses cross, draw a circle with your feet 4 cm apart. The circumference of this circle is () cm and the area is () cm2.

2. Cut out the largest circle on a square paper with a side length of 4 cm. The radius of this person is () cm and the circumference is () cm.

3. Draw the largest circle in a rectangle with a length of 10 cm and a width of 4 cm. The radius of this circle is () cm and the circumference is () cm.

4, a ring, the radius of the inner circle is 6 decimeters, the radius of the outer circle is 8 decimeters, and the area of this ring is () square decimeters.

5. A circular nursery with a perimeter of15.7m and an area of () m2. If you plant a tree every 3 meters around this circular nursery, you can plant about () trees. If you plant chrysanthemums in this circular garden, the area of planting chrysanthemums is about () square meters.

6. Divide a circle into several parts. The approximate length of a rectangle is 15.7 decimeter, the perimeter of the rectangle is () decimeter, and the area of the circle is () square decimeter.

Second, the judgment (10)

1, the line segment with both ends on the circle is called the diameter. ( )

2. In the same circle, two radii are a diameter. ( )

The circumference of any circle is always 2π times its radius. ( )

The circumference of a semicircle is half that of a circle. ( )

5. When the radius of a circle increases by 1 cm, its circumference increases by 2 cm. ( )

Iii. Selection (15)

1, with the same length of iron wire respectively surrounded by a rectangle, a square, a circle, () the smallest area.

A, square b, circle c, rectangle

2. The diameter of the circle and the side length of the square. , compare their areas, and the result is ()

A, the square area is larger than B, and the circular area is larger than C, and they are equal.

3, a circle, its outer circle diameter is twice the diameter of the inner circle, the area of the circle ().

A, B are larger than the area of the inner circle, and C is smaller than the area of the inner circle, which is equal to the area of the inner circle.

4. Divide a circular iron sheet with a diameter of 2 cm into four parts along two vertical diameters, and then calculate the perimeter () and area ().

A, bigger B, smaller C, unchanged.

4. Find the area of the shaded part in the figure below. (10)

1. The outer circle at the lower left is 8 cm in diameter.

The square on the lower right is 4 meters long.

V. Operational problems (9 points)

Draw a semicircle with a diameter of 4 cm with O as the center, and find its circumference.

Six, solve the problem (32 points)

1. The diameter of the round flower bed is 8 meters. If the surrounding area is widened by 2 meters, how many square meters will the flower bed area increase?

2. There is a rope with a length of 3 1.4 meters. Xiao Zhang used this rope to play games in a round field on the playground. What is the area of this field?

Xiao Lin and Xiao Hong walk in the same place in opposite directions on a circle with a diameter of 40 meters. Xiao Lin walks 30.8 meters per minute, and Xiao Hong walks 32 meters per minute. How many minutes did they meet?

4. A small alarm clock, the minute hand is 5cm long. What is the distance of its tip rotation 1 hour?