1,2,3 of the chip pins How to count the order, clockwise or counter clockwise, where to start

The chip is generally square, and there will be a notch or a dot at a certain corner, which is the place to start counting. The chip faces up and starts counting counter clockwise

How to use "start point, end point, radius" to draw arc in VB
Thank you in advance
(it's better to have a procedure example)
What if the starting point and the ending point are variables

Circle
[control or form supporting drawing.] circle (center coordinate X, center coordinate y), radius, [color], arc start point, arc end point [, ratio of radius of ellipse 2]
Here, if the starting point and ending point of the arc are negative, a line connecting the center of the circle to the two points will be made

How to prove that the ratio of the middle line of a similar triangle is equal to the similar ratio

(2) If the two sides of a triangle are proportional to the two sides of another triangle, and the included angles are equal, then the two triangles are similar
(3) If the three sides of a triangle are proportional to the three sides of another triangle, then the two triangles are similar
Judging theorem of right triangle similarity:
(1) A right triangle is divided into two right triangles by the height of the hypotenuse, similar to the original triangle
(2) If the hypotenuse and a right edge of a right triangle are proportional to the hypotenuse and a right edge of another right triangle, the two right triangles are similar
The property theorem of similar triangles
(1) The corresponding angles of similar triangles are equal
(2) The corresponding sides of similar triangles are proportional
(3) The ratio of similar triangle to high line, middle line and bisector is equal to similar ratio
(4) The perimeter ratio of similar triangles is equal to the similarity ratio
(5) The area ratio of a similar triangle is equal to the square of the similar ratio
Transitivity of similar triangles

It is proved that the ratio of the corresponding center line of similar triangle is equal to the similar ratio

The sides of a triangle are proportional to each other. The ratio of the corresponding middle line is equal to the similarity ratio. Don't prove it
To prove is to prove similar triangles

Verification: the ratio of the corresponding midlines of two similar triangles is equal to the similarity ratio (drawing)

Let △ ABC ~ △ a'b'c '
Ad, a'd 'are the midline
Then: BD / b'd '= (BC / 2) / (b'c' / 2) = BC / b'c '
And AB / a'B '= BC / b'c'
So AB / a'B '= BD / b'd'
From △ ABC ~ △ a'b'c ', we can know: ∠ B = ∠ B'
So, △ abd ~ △ a'b'd '
Therefore, the ratio of corresponding median line AD / a'd '= AB / a'B' = similarity ratio

It is proved that the ratio of high line, middle line and angle bisector of similar triangle is equal to the similar ratio

By proving that the triangles of high line, middle line and angle bisector are similar

It is proved that the ratio of the middle line and the bisector of the corresponding angle of a similar triangle are equal to the similar ratio

All are equal to the similarity ratio, that is, the ratio of three sides corresponding to each other. You can use the judgment that two triangles with equal angles are similar to each other to find out this property. I can't draw the figure, but I heard my teacher say that

The corresponding side lengths of two similar polygons are 3cm and 4.5cm respectively. If the sum of their areas is 78cm2, the area of the larger polygon is ()
A. 42cm2B. 52cm2C. 54cm2D. 64.8cm2

Suppose the area of the larger polygon is SCM2, then the area of the smaller polygon is (78-s) cm2, ∵ a group of corresponding side lengths of two similar polygons are 3cm and 4.5cm respectively, ∵ (4.53) 2 = S78 − s, and the solution is s = 54 (cm2)

If both sides of the triangle are 3cm and 5cm long, the value range of the triangle perimeter L is______ ．

Let the length of the third side be X. according to the trilateral relationship of the triangle, we get 5-3 < x < 5 + 3, that is, 2 < x < 8. Therefore, the value range of the perimeter l of the triangle is 5 + 3 + 2 < l < 5 + 3 + 8, that is, 10 < l < 16

The angle bisectors of a group of corresponding angles of two similar triangles are 3cm and 5cm respectively, and their area difference is 48cm2. Calculate the area of the two triangles

The ratio of bisectors equals the similarity ratio
So the similarity ratio is 3:5
The area ratio is equal to the square of the similarity ratio, so the area ratio is 9:25
The difference is 16, so 16 is 48 square centimeters
So one is three square centimeters
So one is 9, one is 25
The answer is 27 square centimeters and 75 square centimeters

1,2,3 of the chip pins How to count the order, clockwise or counter clockwise, where to start