The area of a trapezoid is 50cm, its upper and lower bottoms remain unchanged, and the height will be doubled. At this time, the area of the trapezoid is

The area of a trapezoid is 50cm, its upper and lower bottoms remain unchanged, and the height will be doubled. At this time, the area of the trapezoid is

The unit of area in the question should be "square centimeter"
∵ trapezoid area = 1 / 2 (upper bottom + lower bottom) × height = 50 (CM & # 178;)
(upper bottom + lower bottom) unchanged, the height is expanded by 2 times, that is, only the height is multiplied by 2
The area of trapezoid is: 1 / 2 (upper bottom + lower bottom) × 2 × height = 2 × 50 = 100 (square centimeter)

The project team plans to build a 3 km long highway in 12 days. How many parts of the highway will be built every day on average? How many kilometers will be built every day on average?

On average, one twelfth of the road is built every day;
Average daily repair: 3 / 12 = 1 / 4 km

To build a 7 / 8 km long canal, the engineering team built 4 / 5 of the total length in 4 days. How many kilometers per day on average

[7/8]*[4/5]/[4]

It took 15 days for an engineering team to build a 4 km long road. How many parts of the total length and how many kilometers per day?

Hello, a3355979
How many parts of the total length are repaired every day?
1÷15＝1/15
How many kilometers per day?
4 △ 15 = 4 / 15 (km)

When an engineering team builds a highway, it repairs 1 / 7 of the total length every day on average. How many parts of the total length are repaired in five days?
There are 24 cartons of milk in one carton. How many cartons of such milk are there in 3 / 4 cartons?

1/7×5=5/7
24 × 3 / 4 = 18 boxes

A steel pipe is 12 meters long, cut off 8 meters, how many parts of the total length is cut off? How many parts of the total length is the rest?
A steel pipe is 12 meters long. How many meters are left after 1 / 3 of it is cut off?
A steel pipe is 12 meters long, cut off 1 / 3, how many meters?
Three fourths of the total length of a steel pipe is cut off, which is exactly 9 meters. How many meters is the length of the steel pipe?

12*（1-1/3）=8m
12*(1/3)=4m
9/(3/4）=12 m

A steel pipe is 12 meters long and cut off 8 meters for the first time. How many parts of the total length are cut off for the first time? A steel pipe is 12 meters long and cut off 8 meters for the first time. How many parts of the total length are cut off for the first time? A steel pipe is 12 meters long and cut off 8 meters for the first time?

Two thirds

The length of a steel pipe is 12 meters, and the length of the cut steel pipe is 8 meters. How many parts of the total length is the cut steel pipe? How many parts of the total length is the rest? 2. The length of a steel pipe is 12 meters, and one third of the total length is cut steel pipe
How many meters are left? 3. A steel pipe is cut off, and there are three meters left. How long is this steel pipe? It's urgent

Two thirds, the rest one third
One third of it's eight meters away
The steel pipe is 12 meters long

A steel pipe is 1 / 2 meter long. If 2 / 5 is cut off, how many parts are left? If 2 / 5 is cut off, how many meters are left?

First question:
1-2/5
=3/5
A: there are three fifths left
Second question:
1/2-(2/5)*(1/2)
=1/2-1/5
=5/10-2/10
=3/10
A: there are (3 / 10) meters left

The length of a steel pipe is 12 meters. The worker cut off 8 meters, which accounts for 2 / 3 of the total length. The rest of the total length is (), which is rewritten as a percentage
The output of an automobile factory last year increased by 4% compared with that of the previous year, and last year was equivalent to () of the previous year

1－2／3=1／3=33.3%
Therefore, a steel pipe is 12 meters long, and the worker's master cuts off 8 meters, which accounts for 2 / 3 of the total length, and the rest accounts for (1 / 3) of the total length, and the percentage is (33.3%)
1＋4%=104%=26／25
Therefore, the output of an automobile factory last year increased by 4% compared with that of the previous year, which was equivalent to 104% of that of the previous year (26 / 25)