In △ ABC, AB is equal to AC, and the sharp angle formed by the intersection of the vertical bisector of AB and the straight line AC is 40 degrees, then the vertex angle of the triangle is

In △ ABC, AB is equal to AC, and the sharp angle formed by the intersection of the vertical bisector of AB and the straight line AC is 40 degrees, then the vertex angle of the triangle is

(1) Let AB = AC, if the vertical bisector Mn of AB intersects AC at m,
And M is between AC, from ∠ NMA = 40 ° and  vertex angle ∠ BAC = 90 ° - 40 ° = 50 °
(2) If Mn intersects AC on the extension line, and ∠ NMA = 40 °,
The vertex angle ∠ BAC = 90 ° + 40 ° = 130 °

It is known that: as shown in the figure, in △ ABC, ∠ ACB = 90 °, CD ⊥ AB at point D, point E on AC, CE = BC, make a vertical line of AC through point E, intersect the extension line of CD at point F. verification: ab = FC

It is proved that ∵ Fe ⊥ AC is at point E, ∠ ACB = 90 °, and ∵ FEC = ∠ ACB = 90 °, and ∵ CD ⊥ AB is at point D, and ∵ a + ∠ ECF = 90 °, and ≌ a = ∠ F. in △ ABC and △ FCE, ≌ a = f ≌ ACB = fecbc = CE, ≌ ABC ≌ FCE (AAS), and ≌ AB = FC

Divide 70 pencils among Xiaojun, Xiaoli and Xiaofang. Xiaoli has 12 pencils more than Xiaojun and 8 pencils more than Xiaofang

You set Xiao Li as X
Then you get an equation
X+(X-12)+(X-8)=70
The solution is x = 30, so Xiaoli is 30. According to the title, there are 18 Xiaojun and 22 Xiaofang
Xiaoli 30
Xiaojun 18
Xiaofang 22
Give me points ~!

A pencil is six yuan less than a pen. The unit price of a pencil is one seventh of that of a pen. How many yuan are the pencil and the pen

The pen is:
6÷（1-1\7）
=6÷6\7
=6×7\6
=7 yuan
Pencil is: 7-6 = 1 (yuan)
A: the pencil is 1 yuan and the pen is 7 yuan
I hope my answer can help you,

It costs 55.8 yuan to buy 6 pens and 8 pencils, and 30.3 yuan to buy 3 pens and 8 pencils. What are the unit prices of pens and pencils?

Suppose the unit price of pen is X Yuan and that of pencil is y yuan
6x+8y=55.8
3x+8y=30.3
Solution
x=8.5
y=0.6
The unit price of pen is 8.5 yuan, and that of pencil is 0.6 yuan

The unit price of a pen is six times that of a pencil. What are the unit prices of pen and pencil?

A: a pen costs 7.2 yuan, a pencil costs 1.2 yuan

There are 27 boxes of pens and pencils with 300 pens. There are 10 pens in each box and 12 pencils in each box. How many pens are there?

Suppose all of them are pencils, pens: (12 × 27-300) / (12-10) = 24 / 2 = 12 (boxes). Pencils: 27-12 = 15 (boxes). Answer: there are 15 pencils and 12 pens

My mother bought two pencils and three pens and paid 13.7 yuan in total. A pen costs 1.9 yuan more than a pencil. What's the unit price of a pen and a pencil
Solve by equation and arithmetic

Equation: let pencil X Yuan, pen (x + 1.9) yuan
2x+3（x+1.9）=13.7
2x+3x+5.7=13.7
5x=8
x=8/5=1.6
x+1.9=3.5
Count
1.9 × 3 = 5.7 yuan
13.7-5.7 = 8 yuan
8 (3 + 2) = 1.6 (yuan)
1.6+1.9=3.5

Xiao Ming took some money to buy Stationery. If he bought a pencil of 50 cents, he could buy 8 pencils. If he bought a rubber of 40 cents, how many pencils could he buy? If he just used the money
If you can just buy five exercise books with the money, how much is it

Xiao Ming has four yuan in total
40 / 4 = 10. If you buy a rubber of 4 jiao, you can buy 10 yuan
4 / 5 = 0.8. Each exercise book is 0.8 yuan

Five pencils and nine erasers cost a total of 75 cents. Three pencils and five erasers cost only 43 cents. How much are three pencils and three erasers?

5 pencils and 9 erasers - 3 pencils and 5 erasers = 2 pencils and 4 erasers = 32 cents
Then a pencil and two erasers = 16 cents
Three pencils and five erasers - two pencils and two erasers = two pencils and three erasers = twenty-seven cents
2 pencils and 4 erasers - 2 pencils and 3 erasers = 1 eraser = 5 points
Then a pencil = 6 points
Then, it takes 3x6 + 3x5 = 3 jiao and 3 fen to buy 3 pencils and 3 erasers