The second year of junior high school math problems,,Thank you for just one question

1) Let cq=a, cp=b, pq ab, point p on ac, a=3b 4, when the area of the triangle pqc is equal to the area of the quadrilateral pabq, 1 2*ab=1 2*3b 4=1 2*1 2*3*4b=2 2, a=3 2 2, 2) let cq=a, cp=b, pq ab, point p on ac, a=3b 4, when the circumference of the triangle pqc is equal to the circumference of the quadrilateral pabq, a+b==3-a+(4-b)+5

3b/4+b=3-3b/4+(4-b)+5b=24/7=pc

3) Let cq=a, cp=b, pq ab, point p on ac, a=3b 4 If there is a point m on ab, make the triangle pqm an isosceles right triangle, (if the high school uses the distance between the two parallels to make it more convenient).

Pq = A + B = 25B 16, Pq = 5B 4 take the pq midpoint G, then GM=5B 8

pq ab, distance from p to ab = pq = 5b 8 using similar triangles to obtain:

5b/24=（4-b）/5

b=96/49，a=72/49

pq²=（96²+72²）/49²=14400/49²pq=120/49

I don't know if the answer is right or not, so let's refer to it.

Hook three strands, four strings, five.

Right triangles.

Area ac*bc 2=6

The area of PQC is equal to the quadrilateral ABQP, that is, it is equal to half of the area of the triangle ABC PC QC=AC BC=4 3 (because of PQ AB)PC=(4 3)QC

pc*qc/2=3

Bring in pc=4 root number 2

pq=5 root number 2

Q1: Set: pc=x, pq ab, cpq abc.

Because bc:ac=3:4, qc; pc=3:

4, so the equation (3 4)x = 6-(3 4)x is solved to get 2 times the root number two.

Question 2: Let us: pc=x,, because it is similar, and the circumference is equal, so ab+bq+ap=pc+qc, so the equation is: 5+(3-3x 4)+(4-x)=x+3x 4 solution: x=24 7

We note that ; There are a total of 10 (5 pairs) of this regular number, and every two adjacent numbers are 10 apart, then: 12 to 1002 has 50 pairs (100) of such combinations (numbers), so 1002 -992 +982-972 +962 -952 +....42-32+22 -12 =50*10=500

Convert x square meters of office space into commercial space.

600-x)*12*4=(400+x)*48 gives x=100

Therefore, the 100-square-meter office space was converted into a commercial space.

Convert x square meters of office space into commercial space.

12 (600-x) * 4 = 48 (400 + x) x = 100 square meters.

The 100-square-meter office space will be converted into commercial space.

Hope it helps.

Convert x square meters of office space into commercial space.

Then 4*12(600-x)=48(400+x).

Solution x = 100 square meters.

Find a way to get a 30-degree angle, and you're good to go.

1. S A=

2. S B = B catches up with A, that is, S A = S B.

t=3。

(1) There is a line segment on the map that has not changed the distance, that section is the time he stays 1h B is the top point, the left of the point is the image when he goes, the right is the image of his return, the distance is 60, and it takes 2 hours.

so his speed is 30kmh

I'm sorry, landlord, I won't be able to do the ones below. I'm stupid, hehe.

The first few questions are really simple, so let's do it yourself. Question 3: Draw Xiao Wang's functional relationship on that diagram, and then see how many intersections there are to meet a few times.

On AD,,AE parallel BC,There are two groups of internal wrong angles that are equal, angle AME=angle BMC to apex angle,Triangle AME=CB=6 3=2,Point E is on the straight AD extension line,,Similarly, triangle AME=CBaMEsimilar triangle CMB,,MC AM=CB AE=6 (6+3)=2 3

e when on AD.

Connect the midpoint of D and BC, intersect with AC and N, and DN is parallel to BE, because the parallel lines are divided into line segments in equal proportions, so AM=MN=NC, so it should be 2:1

If it is on the extension line, then extend the cb cable to the n point so that cb=bn, and the same can be obtained by connecting dn, mc:am=1:2

If you try to draw a diagram, when the point E is the midpoint of AD, the triangle EAD is similar to the triangle ECB, and the ratio of the corresponding sides is 1:2, so MC AM=2:1, and in the same way, when E is on the extension line of AD, MC AM=2:3

The process is the same in both cases. For the triangle ame and the triangle cmb, the angle ame angle bmc, the angle eam angle bcm, so the triangle ame is similar to the triangle cmb. So mc am=cb ae

If E is on AD, then AE 3, if on the extension line, then AE 9, so MC AM = 2:1 or 3:2