What is the circumference and area of a circle? Don't be too complicated. Come on

What is the circumference and area of a circle? Don't be too complicated. Come on

Perimeter: 3.14 times diameter
Area: 3.14 times the square of radius

What is the circumference and area of a circle

C is equal to π D or 2 π R D is the diameter R is the radius C is the circumference of the circle π is the circumference π equals 30141592653
S equals the square of π R, s is the area of the circle, and the square of π R is π R * π R

As shown in the figure, OA ⊥ ob, OC ⊥ OD=______ ．

∵ OA ⊥ ob, OC ⊥ OD, ∵ AOB = ∠ cod = 90 °; and ∵ AOD + AOB + BOC + cod = 360 °, AOD = 144 ° and ∵ BOC = 36 °; so the answer is: 36 °

4. If AOB = 50 degrees and BOC = 30 degrees are known, AOC will be the same=__________ , or__________ .

If AOB = 50 degree and BOC = 30 degree, AOC = 80 degree or 20 degree

It is known that ∠ AOB = 3 ∠ BOC, if ∠ BOC = 30 °, then ∠ AOC=______ Degree

∵ - BOC = 30 °, ∵ AOB = 3 ∵ BOC, ∵ - AOB = 3 × 30 ° = 90 ° (1) when OC is on the outside of ∵ AOB, ∵ - AOC = ∵ AOB + ∵ BOC = 90 ° + 30 ° = 120 degree; (2) when OC is on the inside of ∵ AOB, ∵ AOC = ∵ AOB - ∵ BOC = 90 ° - 30 ° = 60 degree

It is known that ∠ AOB = 40 ° and there is ray OC in the same plane. If ∠ AOC: ∠ BOC = 3:7, calculate ∠ AOC and ∠ BOC

Because ∠ AOC: ∠ BOC = 3:7 and ∠ AOB = 40 °, AOC + BOC = AOB
So (3 / (3 + 7)) * ∠ AOB = ∠ AOC (7 / (3 + 7)) * ∠ AOB = ∠ BOC
Therefore, AOC = 12 ° BOC = 28 °

In the same plane, if ∠ boa = 70 °, BOC = 15 °, calculate the degree of ∠ AOC

When OC is in the interior of ∠ AOB, ∠ AOC = ∠ boa - ∠ BOC = 55 ° and when OC is in the exterior of ∠ AOB, ∠ AOC = ∠ boa + ∠ BOC = 85 ° so ∠ AOC = 55 ° or 85 °

In the same plane, if ∠ AOB = 70 degree ∠ BOC = 15 degree OE bisects ∠ AOC, calculate ∠ AOE

Should there be a picture
The BOC is within the range of AOB
∠AOE=1/2(∠AOB-∠BOC)
∠AOE=1/2(70°-15°)
∠AOE=1/2(55°)
∠AOE=27.5°
The BOC is outside the AOB
∠AOE=1/2(∠AOB+∠BOC)
∠AOE=1/2(70°+15°)
∠AOE=1/2(85°)
∠AOE=42.5°

As shown in the figure, the ratio of degree between ∠ AOC and ∠ BOC is 5:3. Od bisects ∠ AOB. If ∠ cod = 15 °, calculate the degree of ∠ AOB

Let ∠ AOC = 5x °, then ∠ BOC = 3x °. ≠ AOB = ∠ AOC + ∠ BOC = 8x ° ∵ od bisection ∠ AOB, ≠ AOD = 12 ∠ AOB = 4x °. ∵ cod = ∠ AOC - ∠ AOD, ∵ 5x-4x = 15, ∵ x = 15. ∵ AOB = 8x ° = 8 × 15 ° = 120 °. So the answer is: 120 °

In the same plane, given that the angle AOC is equal to 60 ° and the angle AOB: the angle BOC is equal to 1:2, calculate the degree of ∠ BOC
In two cases, we should use unknowns

∵∠ AOB: ∠ BOC = 1:2 and ∠ AOB + ∠ BOC = ∠ AOC
■ ∠ BOC = 2 / 3 [two thirds] ∠ AOC = 2 / 3 [two thirds] × 60 ° = 40 °
A: the degree of BOC is 40 degrees