As shown in the figure, a ladder AB is 2.5m long, the top a is against the wall AC, and the distance between the bottom B of the ladder and the corner C is 1.5m; The ladder stops at the de position after sliding. As shown in the figure, BD = 0.5m is measured. How many meters does the top a of the ladder fall? Please use the method of column equation to solve application problems, and set up equations if necessary

As shown in the figure, a ladder AB is 2.5m long, the top a is against the wall AC, and the distance between the bottom B of the ladder and the corner C is 1.5m; The ladder stops at the de position after sliding. As shown in the figure, BD = 0.5m is measured. How many meters does the top a of the ladder fall? Please use the method of column equation to solve application problems, and set up equations if necessary

Set down x meters
（2-x)^2+(1.5+0.5)^2=2.5^2
We obtain that x = 0.52-x is EC 1.5 + 0.5 is CD and apply Pythagorean theorem

As shown in the figure, a 2.5-meter-long ladder AB leans against a vertical wall AC. at this time, the distance between the foot B and the bottom C of the wall is 0.7 meters. If the top of the ladder slides 0.4 meters along the wall, how many meters will the foot move outward?

In the right angle △ ABC, if AB = 2.5m and BC = 0.7m, then AC = 2.52 − 0.72M = 2.4m, ∵ AC = Aa1 + CA1 ∵ CA1 = 2m, ∵ in the right angle △ a1b1c, ab = A1B1, and A1B1 is hypotenuse, ∵ CB1 = (& nbsp; A1B1) 2 − (CA1) 2 = 1.5m, ∵ BB1 = cb1-cb = 1.5m-0.7m = 0.8m A: the foot moves outward by 0.8m

The blackboard in the classroom is 3M long and 1.5m wide. Please choose a suitable scale to draw the schematic diagram of the blackboard
Just the formula. No drawing

Length:
3m=300cm
300×1/100=3cm
Width:
1.5m=150cm
150×1/100cm

Students paint a 8.5m long, 7m wide and 3M high classroom. (1) after deducting 36m2 of doors, windows and blackboard, how many square meters is the painting area? (2) If every square metre uses coating 8.5 yuan, how many yuan to buy coating altogether?

(1) 8.5 × 7 + 8.5 × 3 × 2 + 7 × 3 × 2-36 = 59.5 + 51 + 42-36 = 116.5 (square meters); answer: the area to be painted is 116.5 square meters. (2) 8.5 × 116.5 = 990.25 (yuan); answer: a total of 990.25 yuan to buy paint

Measure the length of the classroom blackboard is 3 meters and the width is 1 meter, and then draw the plan of the blackboard according to the scale of 1:100

Scale = distance on the map △ actual distance
Length: 3 M = 300 cm, 300 × 1 / 100 = 3 cm
Width: 1 m = 100 cm, 1 / 100 × 100 = 1 cm
Therefore, the blackboard on the plan is 3cm long and 1cm wide. The area is 3cm square

As shown in the figure, a 3 m long and 1.5 m wide rectangular blackboard ABCD is as shown in the figure, and the wooden frame inlaid on its periphery is 7.5 cm wide. Is the rectangle ABCD formed by the inner edge of the frame similar to the rectangle efgh formed by the outer edge of the frame? Why?

In rectangular ABCD, ab = 1.5 m, ad = 3 m, the width of wooden frame is 7.5 cm = 0.075 m, EF = 1.5 + 2 × 0.075 = 1.65 m, eh = 3 + 2 × 0.075 = 3.15 m, abef = 1.51.65 = 1011, AdeH = 33.15 = 2021, ∵ 1011 ≠ 2021, and the inner edge of rectangular ABCD and frame

Xiao Ming's room is 4 meters long and 3 meters wide. He wants to draw the floor plan of the room. Please refer to it for Xiao Ming. What scale is appropriate?
I need the method to solve the problem, do not say a rate does not adopt!

4m = 400cm, 3M = 300m
According to the scale of 100:1, it grows to 4cm and 3cm in width

Xiao Ming's room is 4 meters long and 3 meters wide. He wants to put the plane picture of the room on A4 paper. Can you help Xiao Ming to refer to it and choose a suitable scale?
Explain the reason, do not explain not to adopt

4m = 400cm, 3M = 300m
According to the scale of 100:1, it grows to 4cm and 3cm in width

A precise part is 15mm long. Uncle Wang drew it on the drawing, measuring 18cm long. What's the scale of this drawing?
Solve it in the way of proportion

180/15=12:1 1:1.2

A part is 4mm long and 20cm long when drawn on a drawing. What is the scale of this drawing?
Another question: what is the numerical scale of the line segment scale from 0-20-40-60-80 km (the one in the middle represents one centimeter)~

20 cm = 200 mm
Scale = 4:200 = 1:50
20km = 2000000cm
Rewrite to a numerical scale of 1:2000000