A 6th grade question about the area of a circle, 5 marks

The area of the circumscribed square of the circle is 2*r*r, and the area of the circle is, so the area of the inscribed square is 2 far. So the area of this inscribed square is:

square decimeters).

r^2=

Radius r = 4 diameter d = 2 * 4 = 8

The side length of the square is a, and according to the Pythagorean theorem, a 2 + a 2 = d 2a 2 + a 2 = 64

a^2=32

This is the area of the square s=a2=32 square decimeters.

Step 1: Calculate the radius based on the area of the circle.

r 2 = radius r = 4 Step 2: Calculate the side length of the square.

Side length = 4 2

Step 3: Find the area of the square.

Area = 32<>

It can be deduced that the radius is 4cm

4 2 4 = 16 square centimeters.

Draw a circle with the largest square abcd center o o to ab center distance ae The key is the ae length.

The principle obtains that the area is the largest when ae=2 branch root number 2r.

The area of the circle in Primary 6 math is as follows:

Fill-in-the-blank questions.

Divide a circle into equal parts, cut them and put them together into an approximate rectangle. The length of this rectangle is equivalent to ( ) The width of the rectangle is the circle ( ) Because the area of the rectangle is ( ), the area of the circle is ( ).

The diameter of the circle is 6 cm, and its circumference is ( ) and the area is ( ).

The circumference of a circle is decimeters, and its area is ( ).

The radius of circle A is 3 times the radius of circle B, the circumference of circle A is the circumference of circle B ( ) and the area of circle A is the area of circle B ( ).

The radius of a circle is 8 centimeters, and the area of this circle is 3 4 square centimeters.

Rectangles, squares, circles with equal circumference, ( The area is the largest.

Vocabulary questions.

There is a sheep tethered to a stake in the grass, and the length of the rope is 4 meters, how many square meters of grass can this sheep eat?

After a grenade **, the radius of the effective killing range is 8 meters, and the effective killing area is how many square meters?

An aluminum basin is stamped from a round aluminum plate with a diameter of 30 centimeters, how many square meters of aluminum plate is needed to make 1000 such basins?

The set of points in the same plane whose distance to a fixed point is equal to a fixed length is called a circle. A circle can be represented as a set, where O is the center of the circle and R is the radius of the plexus. The standard equation for a circle is (x-a) +y-b) = r, where the points (a, b) are the center of the circle and r is the radius.

The area formula for a circle is as follows:

s= r (r—radius, d—diameter, —pi).

By dividing the circle into equal parts, you can put together an approximate rectangle. The width of the rectangle is equal to the radius of the circle (r), and the length of the rectangle is half of the circumference of the circle (c). The area of the rectangle is ab, and the area of the circle is:

The square of the radius (r) of the circle is multiplied by . That is, the area of the circle = the radius radius of pi.

The properties of the circle are as follows:

1. The circle is an axisymmetric figure, and its symmetry axis is any straight line passing through the center of the circle. A circle is also a center-symmetrical figure, and its center of symmetry is the center of the circle.

Perpendicular diameter theorem: Bisect the string perpendicular to the diameter of the string, and bisect the 2 arcs of the chord opposite.

The inverse theorem of the perpendicular diameter theorem: the diameter of the bisector chord (not the diameter percolation) is perpendicular to the chord, and the 2 arcs of the bisector chord are opposed.

2. The properties and theorems of circumferential and central angles are as follows:

In the same circle or equal circle, if one set of quantities in two central angles, two circumferential angles, two sets of arcs, two strings, and two chord center distances are equal, then the rest of the groups of quantities corresponding to them are equal.

In an identical or equal circle, the circumferential angle of an equal arc is equal to half of the central angle of the circle to which it is opposite (the circumferential angle is on the same side as the central angle of the chord).

1.A circle, cut from the center of the circle along the radius, is put together into an approximate rectangle. It is known that the circumference of the rectangle is 6 cm longer than the circumference of the circle, find the area of the circle.

Untie; (6 2) squared =

2. A circular piece of paper, the outer radius is 10 cm, the inner radius is 8 cm, how many square centimeters is the area of this circular piece of paper?

Solution: (10 squared) 8 squared ) = 36 =

The area s= r, which is the pi, is the pi, and is usually taken, and r is the radius of the circle.

According to the formula for the circumference of a circle 2, r 100 decimeters, the formula for the area of a circle is square decimeters.

Answer: The area of the circle is 31,400 square decimeters.

The circumference of the circle is 628 decimeters, and the radius is.

628 decimeters) area is.

31400 (decimeter).

A: The area of this circle is 31,400 decimeters.

Since the circumference of the circle = 2 r = 628 decimeters, the radius of the circle is 628 2 decimeters.

So the area of the circle is r = square decimeter.

The circumference of the circle = d, d = 2r

628 decimeters.

Area of the circle = r

square decimeters).A: The area of this circle is 31,400 square decimeters.

Radius: 628 (2 dm.)

Area: square decimeters.

The diameter of the circle = the length of the diagonal of the square = 10 2 The length of the sides of the square: the diagonal = 1: 2 The semi-deficit diameter of the circle = 5 2 2 Area = *5 2*5 2 = 50 = 157 square centimeters The ratio of the square to its circumference is 0,63694:

1 =10 10 0,63694 =100 0,63694 =157 Job Help user 2017-09-24 Report.

One is a semicircle with a diameter of 4, and the other is an arc with a radius of 4 and an angle of 45 degrees. Find the area of the shaded part.

From a circle with a diameter of 8 cm, after cutting off the largest square, how much area is left of the circle?

The side length of the square is equal to the radius of the circle, and the area of the square is equal to 75 square meters, find the area of the circle?

This is what my child did just the other day.

10 4 square centimeters.

The area of the garden is squared centimeters.

The area is 10 cm?? The area is 10 square centimeters.

The area of the circle: 10 square centimeters).

The area of the largest circle within a square is 25% of the area of the square