The bottom of a triangle is 4 meters long. If the bottom is extended by 1 meter, the area will be increased by 2 square meters. What is the original area of the triangle

The bottom of a triangle is 4 meters long. If the bottom is extended by 1 meter, the area will be increased by 2 square meters. What is the original area of the triangle

It's 8

The length of the bottom of a triangle is 4 meters. If the bottom is extended by 1 meter, the area will be increased by 2 square meters?

It's not easy!
The bottom is extended by one meter, and the height is equal to the original triangle, so the height can be calculated as 2 × 2 △ 1 = 4m
The original triangle area: 4 × 4 △ 2 = 8m & sup2;

A rectangular sheet of iron, 60 decimeters long and 40 decimeters wide. How many sheets of iron are left after six largest circles of equal area are cut out with it

It is easy to know: 3 gardens can be cut along the long side, each garden diameter is 60 / 3 = 20, and 2 gardens can be cut in the direction of just width
So the remaining area is: 60 * 40-6 * 10 * 10 * 3.14 = 516 (square decimeter)

Cut out the largest circle from a rectangular sheet of iron 6 decimeters long and 4 decimeters wide. What is the area of the circular sheet of iron, and what is the area of the remaining sheet of iron
What percentage of the area of the original rectangle

The area of circular iron sheet is 0.2 * 0.2 * 3.14 = 0.1256 square meters
The percentage of the remaining sheet area in the original rectangular area is: (0.6 * 0.4-0.1256) / (0.6 * 0.4) = 47.67%

At present, on a rectangular sheet of iron 20 decimeters long and 15 decimeters wide, four small squares of equal area should be cut off from its four corners and folded into one
How many decimeters is the side length of each small square to make the bottom area of the box 126 square decimeters?

Let the side length of each small square cut out be x decimeter, then it is obtained from the condition
(20-2x)(15-2x)=126
2x^2-35x+87=0
X = 3, x = 14.5 (rounding off)
Answer: when the side length of each small square is 3 decimeters, the bottom area of the box can be 126 square decimeters

① Cut a sheet of iron 4 decimeters long and 3 decimeters wide into the largest circle. How many square decimeters is the remaining area?
② The school is going to build a round flower bed with a circumference of 25.12 meters. A circular path with a width of 1 meter is paved around it. How many square meters does this path cover?
③ : the roller of a roller is 12 meters long and 1.2 meters in diameter. If it rolls 20 times, how many meters will it advance? What is the area of the road it presses?

① Cut a sheet of iron 4 decimeters long and 3 decimeters wide into the largest circle. How many square decimeters is the remaining area?
4×3-3.14×（3/2×3/2）
=12-7.065
=4.935 square decimeters
② The school is going to build a round flower bed with a circumference of 25.12 meters. A circular path with a width of 1 meter is paved around it. How many square meters does this path cover?
Inner radius 25.12 △ 3.14 △ 2 = 4m
Outer radius 4 + 1 = 5m
Area 3.14 × (5 × 5-4 × 4)
=3.14×9
=28.26 square meters
③ : the roller of a roller is 12 meters long and 1.2 meters in diameter. If it rolls 20 times, how many meters will it advance? What is the area of the road it presses?
Distance 3.14 × 1.2 × 20 = 75.36m
Area 75.36 × 12 = 904.32 square meters

1. Cut a piece of iron sheet with a length of decimeter and a width of 3 decimeter into the largest circle, minus the area of square decimeter
2. There is a round flower bed with a diameter of 12M, and a 2m wide path is paved around the flower bed. What is the area of the path?
It's 4 decimeters long

1. The area of iron sheet s Iron = 4dm * 3DM = 12dm & # 710; 2 the area of the largest circle s circle = π R & # 710; 2 = 3.14 * (1.5dm) &# 710; 2 = 7.065dm & # 710; 2 the subtracted area s = s iron-s circle = 12dm & # 710; 2-7.065dm & # 710; 2 = 4.935dm & # 710; 22 the flower bed radius is 6m, the area of the ring is 12M, the outer circle is 12m

There is a piece of iron sheet with an area of 1 square meter. After being cut off a rectangle with a length of 6 decimeters and a width of 4 decimeters, what is the area of the remaining part?

The total volume subtracts the area to be cut off. The area to be cut off is 24 decimeters square, which is 0.24 square meters. The remaining area is 1-0.24 = 0.76 square meters

There is a rectangular sheet of iron, 60 cm long and 40 cm wide. How many sheets of iron are left after six largest circles of equal area are cut out with it

The diameter of the six largest circles of equal area is 20 cm
The radius is 10 centimeters
The remaining area of iron sheet
=Rectangular sheet area - area of 6 circles
=60*40-（3.14*10*10）*6
=2400-1884
=516 square centimeters

Cut a square as large as possible from a right triangle iron sheet (the length of the right side is 10 cm and 30 cm respectively)
What is the area of a square

56.25