Which direction is clockwise or counterclockwise

Which direction is clockwise or counterclockwise

Clockwise and counterclockwise judgment
How to judge clockwise and counter clockwise? Is it clockwise when turning from west to east?

For example: in the plane rectangular coordinate system, taking o as the center of the circle, the process of drawing a circle from a point on the positive half axis of X to the positive half axis of y can be regarded as a counter clockwise movement; the process of drawing a circle from a point on the positive half axis of X to the negative half axis of y can be regarded as a clockwise movement; it is not that "turning from west to East is a clockwise needle"

Which direction is clockwise? Which direction is counterclockwise

Clockwise is from left to right, counter clockwise is from right to left

How many degrees clockwise is 270 degrees counter clockwise

270 degrees counter clockwise is 90 degrees clockwise

Find the side length and area of inscribed regular triangle of a circle with radius of 20
The analysis should be comprehensive

Let ABC be inscribed with circle O, connect Ao, intersect circle O with D, intersect BC with E, and connect BD,
Then in RT ⊿ abd, Ao = 40, angle DAB = 30 degrees, ab = 20 √ 3, AE = 20, namely AB = AC = BC = 20 √ 3,
S⊿=BC*AE/2=200√3.
So the side length of the triangle is 20 √ 3, and the area is 200 √ 3

In △ ABC, a, B and C are the opposite sides of angles a, B and C respectively, C = 2A, a + C = 10 and cosa = 34

(I) C = 2A, cosa = 34, using the sine theorem, CA = sincsina = sin2asina = 2sinacosasina = 2cosa = 32; (II) from a + C = 10 and Ca = 32, a = 4, C = 6, from cosa = B2 + C2 − a22bc = B2 + 36 − 1612b = 34, B 2-9b + 20 = 0, B = 4 or B = 5

In △ ABC, a = 3, B = 2 root 6, ∠ B = 2 ∠ a, (1) find the value of cosa, (2) find the value of C

(1) By using the sine theorem a / Sina = B / SINB ∫ B = 2 ∠ a, then a / Sina = B / sin2a, that is, B / a = sin2a / Sina = 2cosa ∫ 2cosa = 2 √ 6 / 3 ∫ cosa = √ 6 / 3 (2) using cosine theorem a square = b square + C square - 2BC * cosa to substitute a = 3, B = 2 √ 6 ∫ 9 = 24 + C square - 4 √ 6 * (√ 6 / 3) C ∫ C square

In △ ABC, if cosa = 45, C = 120 ° and BC = 23, then ab=______ ．

∵ cosa = 45, a is the inner angle of triangle, ∵ Sina = 1 − cos2a = 35, ∵ sinc = sin120 ° = 32, BC = 23, ∵ from the sine theorem absinc = bcsina, ab = bcsincsina = 23 × 3235 = 5

In △ ABC, if BC = 1, angle c = 120 ° and cosa = 2 / 3, then ab=

From cosa = 2 / 3, we get: Sina = (radical 5) / 3, from the sine theorem: BC / Sina = AB / sinc, we get: ab = three times of ten, radical 15

In triangle ABC, ab = 2, BC = 3, a = 4, then cosa=
With a = 4,
Please advise

A = 4. In other questions, it can be 4 radians
In this problem, it may mean AC = 4, otherwise,
It's meaningless to ask cosa =