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As shown in the figure below, the area of rectangle ABCD is 12 square decimeters, so the area of circle is () square decimeters Well, there is no picture. Let's give a brief description There is a circle, no matter how big, half of it (that is, a semicircle). Draw a rectangle on the semicircle. The length of the rectangle is equal to the diameter of the circle. Then say that the area of the rectangle is 12 square decimeters. Tell the area of the whole circle. Thank you!
What is the width of a rectangle? Is it equal to the radius of a circle
If it's equal to
Let the radius of the circle be r
2R square = 12
R square = 6
The area of the element is 6 π
The area of the circle in the figure is exactly 12 times that of the rectangle ABCD. The length of AB is 6.28cm, and the area of the shadow is______ Square centimeter
3.14 × (6.28 △ 2) 2 × 1.5 = 3.14 × 9.8596 × 1.5 = 30.959144 × 1.5 ≈ 46.44 (square centimeter); answer: the area of shadow part is 46 square centimeter. So the answer is: 46.44
As shown in the figure, in the quadrilateral ABCD, ab = 8, ad = 6, CD = 24, and angle a = 90 degrees. Request the area of this quadrilateral ABCD
Because angle a = 90 degrees, triangle abd area = 1 / 2 * AB * ad = 24
Triangle BCD area = 1 / 2 * CD * ad = 72
So quadrilateral ABCD area = triangle abd + triangle BCD = 96
Find the value of DF: FC with ladder ABCD, ad ‖ EF ‖ BC, ad = 4, EF = 5, BC = 7
It is easy to get that the triangle AGD is similar to the triangle EGF, so GD / GF is equal to
Ad / EF can easily get that GD is equal to 4df, and triangle AGD is similar to triangle BGC, so ad / BC is equal to GD / GC
GD / GC equals 4 / 7, so GD / DC equals 4 / 3, that is, 4df / DC equals 4 / 3, so DF / DC equals 1 / 3, so DF / FC equals 1 / 2
As shown in the figure, in the tetrahedral ABCD, e and G are the midpoint of BC and ab respectively, f is on CD, h is on ad, and DF: FC = 2:3, DH: Ha = 2:3
It is proved that: connecting Ge, HF, ∵ E and G are the midpoint of BC and AB, respectively, ∵ Ge ∥ AC. DF: FC = 2:3, DH: Ha = 2:3, ∩ HF ∥ AC. ∥ Ge ∥ HF. Therefore, G, e, F and H are coplanar. Furthermore,
RELATED INFORMATIONS
- 1. In the quadrilateral ABCD, BD bisects ∠ ABC, AC ⊥ BD at R, PQ intersects BC and ad at points Q and P respectively, and ∠ bad = ∠ BQP
- 2. As shown in the figure, ad ∥ BC in ladder ABCD, point E is the midpoint of edge ad, connecting be with AC at point F, the extension line of be with CD at point G, verify Ge / GB = AE / BC
- 3. As shown in the figure, in ladder ABCD, ab ‖ CD, e is the midpoint of DC, the line be intersects AC at F, and the extension line of ad intersects g; verification: EF · BG = BF · eg
- 4. Take a point G on the extension line of one side of the square ABCD and connect it with a, intersect BC at point F, connect diagonal BD and intersect AF at point E. AE = 5, AF = 3 are known, and calculate the length of FG chart
- 5. In quadrilateral ABCD, ad = BC, AE, CF are perpendicular to BD, be = DF. It is proved that quadrilateral ABCD is parallelogram I can't find the last condition in the verification. Please give me some advice. Thank you
- 6. In square ABCD, point G starts from point C and moves along CB; point h starts from point a and moves along Ba, and two points move at the same speed and stop at the same time
- 7. In the parallelogram ABCD, there is a point E on the side of DC, which connects AE. The point F is on the side of AE, and connects B. It is proved that the triangle ABF is similar to the triangle EAD Angle BFE is equal to angle C
- 8. ABCD is a parallelogram, e and F are the midpoint of AD and BC respectively
- 9. In the quadrilateral ABCD, the diagonal AC bisects ∠ bad, AB > ad
- 10. It is known that e is the edge of the parallelogram ABCD, AB extends to the upper point, de intersects BC with F. proof: the area of the triangle ABF is equal to the area of the triangle efc Mathematics in grade two
- 11. The perimeter of parallelogram ABCD is 75cm, the height is 14cm with BC as the bottom (as shown in the figure); the height is 16cm with CD as the bottom. Calculate the area of parallelogram ABCD
- 12. In the trapezoidal ABCD, point P starts from point a and moves along the edge of ad to point d at a speed of 1cm / s, and point Q starts from point C and moves along CB to point B at a speed of 2cm / s. if points P and Q start from two points at the same time, when one of them reaches the end point, the other stops moving. (1) what is the value of T when trapezoidal pbqd is a parallelogram? (2) What is the value of T when trapezoid pbqd is isosceles trapezoid?
- 13. In the parallelogram ABCD, M is the midpoint of BC, n is on AB, BN = 1 / 2An, NM intersects BD with G, and BG: GD is obtained
- 14. In the parallelogram ABCD, be ⊥ ad, BF ⊥ CD, the perpendicular foot is e, F, the perpendicular center of △ bef is h, if DG ⊥ BC, the perpendicular foot is g It should be verification: BH = GF
- 15. In trapezoidal ABCD, AB / / CD, AC is vertical to BD, angle BDC = 60 degrees, AC = 3 root sign 3, find the length of BD and the area of trapezoidal ABCD In the isosceles trapezoid ABCD, ab = 2CD, AC bisects DAB, ab = 4, ab ‖ CD, (1) Find the trapezoid angle; (2) find the trapezoid area
- 16. In a circle with a radius of 12 decimeters, draw a square, draw a small circle in the square, and calculate the area of the small circle
- 17. In the diamond ABCD with side length of 2, ∠ bad = 60 °, e is the midpoint of AB, P is the upper moving point of AC, and the minimum value of Pb + PE is obtained
- 18. In rectangular ABCD, BC = 4, BG is perpendicular to diagonal AC and intersects AC, ad and ray CD at points e, F, G, ab = x respectively. (1) when point G coincides with point D, calculate the value of X; (2) when point F is the midpoint of AD, calculate the value of X and the sine value of ∠ ECF
- 19. As shown in the figure, points E and F are points on edge BC and CD of diamond ABCD respectively, and ∠ EAF = ∠ d = 60 ° and ∠ fad = 45 °, then ∠ CFE=______ Degree
- 20. As shown in the figure, in diamond ABCD, ∠ bad = 60 °, M is the midpoint of AB, P is a moving point on the diagonal AC, if the minimum value of PM + Pb is 3, then the length of AB is () A. 3B. 3C. 6D. 23