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After adding 3cm to the two adjacent sides of a square, we get a new square. The area of the new square is 39 square centimeters larger than that of the original square. What's the area of the original square?
Let the side length of the original square be x cm. According to the meaning of the title, we can get: 3x + 3x + 3 × 3 = 39 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 6x + 9 = 39 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 6x = 30 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 5 the original square
When the side length of a square lawn is increased by 3 meters, the area will be increased by 39 square meters. How many square meters is the original area
Suppose that the original side length of the square is a and the area is a * a, then the original side length increases by 3 meters, the side length becomes (a + 3), and the new area is (a + 3) * (a + 3). According to the problem, the area increases by 39 square meters, so (a + 3) * (a + 3) - A * a = 39, the solution is a = 5, and the original area is 5 * 5 = 25m * 2. I hope it can help you
A section of 7m long iron wire is cut into 9 sections on average, and each section is () m long
Each section is one ninth of the length of the wire, and each section is seven ninths of the length
Circle the wire around the equator of the earth. If the wire is increased by 15.7m, the circle of the wire will leave the ground evenly
fifty-five thousand eight hundred and twenty-eight
I understand what you said, but what are you asking?
There is a triangle with side lengths of 0.8m, 1.5m and 1.7m. How to cut out the largest circular cover and find out the surface of the circular cover
It's the inscribed circle
Let R be the radius
S triangle = 1 / 2R (0.8 + 1.5 + 1.7) = 1 / 2 * 0.8 * 1.5
R=0.3
The area of the circle is 0.09 π
If the length of three sides of a triangle is known, calculate the area? If the length of three sides is 31.7m, 30.7m and 21.7M, calculate the area
Area: S = ah / 2
(2) If three sides a, B and C of a triangle are known, then (Helen formula) (P = (a + B + C) / 2)
S=√[p(p-a)(p-b)(p-c)]
=（1/4）√[(a+b+c)(a+b-c)(a+c-b)(b+c-a)]
a=31.7 b=30.7 c=21.7
p=42.05
s=317.0541m^2
(3) If the angle c between the two sides of a triangle is known, then s = 1 / 2 * absinc
(4) Let the three sides of the triangle be a, B and C respectively, and the radius of the inscribed circle be r
S=(a+b+c)r/2
(5) Let three sides of triangle be a, B, C respectively, and the radius of circumcircle be r
S=abc/4R
(6) According to trigonometric function, the area is calculated
S= absinC/2 a/sinA=b/sinB=c/sinC=2R
Note: where R is the radius of circumscribed circle
How to calculate the volume of a triangle? It is 0.7m long and the oblique side is 2.3m long
Area of triangle = bottom * height * 1 / 2
Area of right triangle = multiplication of two short sides / 2
Look at the sides perpendicular to the height
The length of the hypotenuse of a right triangle is 10.5m and that of one right triangle is 7m. What is the length of the other right triangle
According to the trilateral relation of right triangle
Square of hypotenuse = sum of squares of two right angle sides
=sqr((10.5^2) - (7^2))
= 7.82623792
1. Xiao Ming wants to circle a triangle with a 2-meter-long wire. If one side of the triangle is 2 / 5 meter, and the other side is 2 / 7 meter, he can circle it
A triangle? Why?
Class 1 and class 2 of grade 5 take part in big break activities on the playground. There are 48 students in class 51 and 42 students in class 52. If the two classes form a team with the same number of people in each column and as many people as possible, how many columns should they stand?
7-7 / 311 + 4-7 / 11=
Please help me, please,
1. No, the triangle must be formed so that the sum of the two sides is greater than the third side, 2 / 5 + 2 / 7 = 24 / 35
Xiao Ming enclosed a triangle with a piece of iron wire. The two sides of the triangle are 8 / 7 meters long and 6 / 5 meters long respectively. How long is the third side of the triangle?
The third side is less than 82 / 35 and more than 2 / 35
RELATED INFORMATIONS
- 1. A circular pool with a radius of 6 meters is surrounded by a circular path with a width of 1 meter. How many square meters is the area of this path?
- 2. Guangming primary school built a semicircular flower bed along a wall. The fence around the flower bed is 31.4 meters long. How many square meters does the flower bed cover?
- 3. The school has built two cylindrical flower beds. The inner diameter of the flower beds is 3 meters, and the height is 0.8 meters. If the height of the filling soil is 0.5 meters, How many cubic meters of soil are needed for the two flower beds?
- 4. Street Park to build a diameter of 12 meters of circular flower bed, around with tiles paved a 3 meter wide path, each tile area is 0.9 square meters Street Park to build a diameter of 12 meters of circular flower bed, around with tiles paved a 3 meter wide path, the area of each tile is 0.9 square meters, how many tiles to use to lay this path?
- 5. There is a flower bed 25 meters long and 20 meters wide. If a 3 meter wide path is built around the flower bed (as shown in the figure), what is the area of the path?
- 6. It is known that the length of rectangular ABCD is 30cm and the width is 20cm. A proper plane rectangular coordinate system is established, and the coordinates of a, B, C and D are obtained first Then the rectangle is made in the rectangular coordinate system ABCD.Thank you
- 7. For a cylindrical pool, the inner wall and bottom of the pool should be inlaid with ceramic tiles. The diameter of the pool bottom is 6 meters, and the pool depth is 1.2 meters. How many square meters is the area inlaid with ceramic tiles?
- 8. For a cylindrical pool, the inner wall and bottom of the pool should be inlaid with ceramic tiles. The diameter of the pool bottom is 8 meters, and the pool depth is 2 meters. How many square meters is the area inlaid with ceramic tiles at most
- 9. As shown in the figure, in the quadrilateral BCDE, angle c = angle, bed = 90 degree, angle B = 60 degree, extend CD, be, get the right triangle ABC The length of BC
- 10. As shown in the figure, in the rectangular coordinate system a (0,1) B (2.0) C (2,1.5) (1) find the area of △ ABC. (2) if there is a point P (a, 1 / 2) in the second quadrant Using the formula containing a to express the area of a quadrilateral abop (3) Under the condition of (2), is there a point P such that the area of the quadrilateral abop is equal to the area of △ ABC? If so, find out the coordinates of point P. if not, explain the reason
- 11. The area of a square flower bed is 225 square meters. How many meters is its side length?
- 12. When the side length of a square increases by 3cm, its area increases by 39cm2. The side length of the square is () A. 5cmB. 6cmC. 8cmD. 10cm
- 13. In the middle of a circular grassland with a girth of 25.12 meters and a flower bed with a radius of 2.5 meters, how many square meters of grassland are left?
- 14. In a round flower bed, half a circle, 141.3m, the radius of this flower bed is
- 15. The diameter of a round flower bed is 8m. How many meters is the perimeter of the flower bed and how many square meters does it cover
- 16. There is a round flower bed in the park, with a diameter of 30 meters. Grandfather Zhang ran around the flower bed for 5 laps in morning exercise. How many meters did he run this time?
- 17. As shown in the picture, a square street garden, the middle is a square flower bed, surrounded by a path, the side length of the flower bed is 12 meters, the width of the path is 1 meter What's the area of the hotel?
- 18. A square flower bed should be built in the park, and a 2m wide lawn should be laid beside the flower bed. The lawn area is 96 square meters. What is the total area of the flower bed and lawn? In the simplest way. No equations
- 19. As shown in the picture, the shape of a 40 meter long vegetable greenhouse is a semi cylindrical shape with a 3-meter-high semi-circular brick wall at both ends. The vegetable greenhouse is covered with plastic film until the end How many square meters less plastic film is needed? How many cubic meters of space is the whole vegetable greenhouse?
- 20. The length of the three wires is 215 meters. One third of the first wire is used, three fifths of the second wire is used, and three fourths of the third wire is used How long are the three wires?