Solve a few math problems, solve a few math problems

The ratio of the top angle to the base angle of an isosceles triangle is 3:1, so what is his base angle? What kind of triangle is he in terms of angles?

The ratio of the top angle to the bottom angle is 3:1, then the ratio of the three angles is 3:1:1, so the base angle is 180 (3+1+1)=36 degrees, and the top angle is 180-36*2=108 degrees, so the triangle is an obtuse triangle.

Take out 1/5 of the salt from warehouse A and transport it to warehouse B, at this time, the quantity of the two warehouses is equal, what is the ratio of the quantity of warehouse A and warehouse B?

A * 4 5 = A * 1 5 + B .

A * 3 5 = B .

Library A: Library B = 5:3

Fast and slow two trains respectively from A and B at the same time, opposite to each other, after hours of meeting, the encounter is more than 25 kilometers to the end point, has been slow train 40 kilometers per hour, fast train travel how many kilometers per hour?

Then the fast train travels 25*2=50 kilometers more than the slow train, and the fast train travels 50 kilometers per hour more than the slow train.

The speed of the express train is 40 + 20 = 60 km/h.

Obviously, on February 18 this year, 300 yuan will be deposited in the bank for a fixed period of one year, and the annual interest rate is to February 18 next year, after deducting the 5% interest tax, how much money will there be?

There are a total of 300+300* yuan.

How many meters can a conical pile of sand with a base area of square meters and a height of 12 meters be used to pave a 2 cm pavement on a 10-meter-wide road?

The volume of the conical shape is 1 3* cubic meters.

Highway cross-sectional area square meters.

I can spread rice.

1 Set the base angle x 5x=180 x=36 obtuse triangle.

2. Let A and B have x y, then x-1 5x=y+1 5x solves the ratio of A and B to 5 3

3. I don't know where the end is.

5 x * 10* Solve x.

Question 1: Suppose that A and B each have A books, A+38=3 (A-72), and the solution is A=84, and A originally has 84 books.

Question 2: Set Wang Ming a score, solve a = 91, Wang Ming 91 points.

1.Let the starting out be x (2 as many anyway).

x+38)=3*(x-72)

Let's figure it out for yourself...

3.Let Wang Ming be x points.

11*85+x)/12=

Let's do it yourself...

1 solution: A bookshelf originally had x books, 3 (x+38) = x-72

The solution is 93

A: There were 93 books on the bookshelf.

3 Solution: Wang Ming x points.

The solution is x = the answer to the king's clear score.

1.Set Xiao Li x years old and grandpa y years old.

5x=y3（x+12）=y+12

Two-way Synopid:

x=12 y=60

So Xiao Li is 12 years old this year, and his grandfather is 60 years old this year.

2.Speed sum: 3 (20 60) = 9 km After the hour meeting, A and B walked another 30-20 = 10 minutes, that is, 1 6 hours, So, A and B walked again: 9 1 6 = km.

The rest of the distance is: kilometers.

The remaining distance of A is twice the remaining distance of B.

Therefore, the remaining distance of B is kilometers.

The remaining distance of A is kilometers.

A walked 3-1=2 km.

B walked a kilometer.

Both walked for hours.

So, the speed of A: 2 km/h.

Speed of B: km/h.

1. Let Xiao Ming's age be x this year, and grandpa's age will be y this year

x=y*1/5

x+12=(y+12)/3

The solution yields x=12 and y=60

2. Let the speed of A be x and the speed of B be y

x/3+y/3=3

3-x*1 2) (3-y*1 2)=2 to obtain x=4, y=5

1.Set Xiao Li x years old and grandpa y years old.

5x=y3（x+12）=y+12

So Xiao Li is 12 years old this year, and his grandfather is 60 years old this year.

2.: 3 (20 60) = 9 km h.

30-20 = 10 minutes, 1 6 hours.

A B 9 1 6 = km.

The rest of the distance is: kilometers.

B is the rest of the kilometer.

The remaining distance of A is kilometers.

A 3-1 = 2 km.

Both of them walked for an hour.

So, the speed of A: 2 km/h.

Speed of B: km/h.

1, Xiao Li is 12 years old.

2. The speed of A is 4km h, and the speed of B is 5km h

1.6 square meters.

Equation: Let the length of the original rectangle be x and the width be y

Then: x-2=y+2

x-2)(y+2)=3xy

The solution is xy = x-y-2

So xy=2

Then the current area is 3xy=2*3=6

2.The answer is in **, with explanation.

12 points) Answer: 24x-30000, 18x or -30000+24x, 18x; 1

Solution: (1) Profit of option 1.

i.e. profit of option 2.

i.e. (2) when x 6000, yuan, yuan.

Option 1 should be chosen

1. Let the current length x, since it is a directional shape, the area is x 2, and it can be seen from the original question that x 2=3(x-2)(x+2).

then x 2 = 6.

2, not very clear, but tower height op=oacos30=oa 3 2; Or a similar triangle can be found.

3:, scheme 1: y1=50x-25x-(2x-30000) 2=24x-15000.

Scheme 2: y2 = 50x-25x-14x 2 = 18x

When x=6000, y1=129000;y2=108000。Therefore, the first treatment should be chosen.

1.Solution:

The volume that falls is the volume of the cone.

v==2826×2

5652 (cubic centimeters).

s=5652×3÷12

1413 (square centimeters).

A: The base area of this cone is 1413 square centimeters.

2.The sides of the cylinder are square, ie.

The bottom surface of the cylinder = the height of the cylinder.

2 r=h so, r h=2

3.A cylinder dissolves into the largest cone, to dissolve the cubic centimeters, that is, their volumes differ by cubic centimeters, and the radius and height of the base are the same, set to r and h respectively, then there is:

r^2h-πr^2h/3=

2πr^2h/3=

Multiply 3 2 by both sides at the same time to get:

r 2h = cubic centimeters).

Answer: The volume of the cylinder before elimination is cubic centimeters.

Cone volume = 30 2*2 = 1800

Let the bottom area of the cone be x, 1 3*x*12=1800

x=450π

1) (30 2)*2 (12*1 3)=450 square centimeters2) set the radius of the bottom surface to r, and the high height h

2πr=h，r：h=1/2π

3) Cubic centimeters.

The volume of the cone is the volume of water falling: cm3, and the formula for calculating the cone is: 1 3 base area * height = 5652cm3. So the area at the bottom of the conic = 5652*3 12 = 1413 cm2

Clearing code circle 2i die digging k

Solution: 11x-k=-31+21

10x=-10

x = -10x10 out of 10

x=-1