If two circles have the same perimeter, they must have the same area______ (judge right or wrong)

If two circles have the same perimeter, they must have the same area______ (judge right or wrong)

If the perimeter of two circles is equal, the radius and area of two circles are equal

If two circles have the same perimeter, they must have the same area______ (judge right or wrong)

If the perimeter of two circles is equal, the radius and area of two circles are equal

As shown in the figure, the center angle of the sector is 120 ° and the radius is R. please imagine that this sector is used to form a cone with height h (excluding the joint). The relationship between the height h of the cone and the radius r of the sector is ()
A. h＞rB. h=rC. h＜r

It is known from the analysis that the sector is used to form a cone with height h (excluding the joint), and the relationship between the height h of the cone and the radius r of the sector is: H < R; therefore, C

As shown in the figure, it is known that ab = CD, the area of △ PAB and △ PCD are equal. Judge whether OP divides ∠ AOD equally, and explain the reason

The reasons are as follows: ∵ AB = CD, △ PAB and △ PCD have the same area, ∵ P has the same distance to OA and OD, ∵ OP has the same distance to AOD (the points with the same distance to both sides of the angle are on the bisector of the angle)

As shown in the figure, it is known that ab = CD, the area of △ PAB and △ PCD are equal. Judge whether OP divides ∠ AOD equally, and explain the reason

The reasons are as follows: ∵ AB = CD, △ PAB and △ PCD have the same area, ∵ P has the same distance to OA and OD, ∵ OP has the same distance to AOD (the points with the same distance to both sides of the angle are on the bisector of the angle)

As shown in the figure, given AB = CD, the area of triangle PAB is equal to the area of triangle PCD

The area of triangle PAB is ab * H / 2, and H is the distance from point P to edge ab

Do ray OA, take D, E on OA, make de = OD

That is to say, the length of OD = the length of de
——————————
O d e a drawing is not accurate, anyway, OD length = de length, in other words
D is the midpoint of OE

The ray OC is in the interior of ∠ AOD. It is known that ∠ AOC = 1 / 5 ∠ AOB. The ray od bisects ∠ BOC, and the degree of ∠ AOB can be calculated by the mutual complement of ∠ doc and ∠ AOC

The ray OC is in the interior of the AOD, so the AOD is equal to cod + AOC = 90 degrees, because the ray od is equal to BOC, so the COD is equal to BOD, because the AOC is equal to 1 / 5 AOB, so the cob is equal to 4 / 5 AOB, so the COD is equal to BOD, so the cob is equal to 1 / 2 × 4 / 5 AOB, because the COD is equal to cod

As shown in the figure, it is known that ray OC divides ∠ AOB into two parts: 1:3 and ray od divides ∠ AOB into two parts: 5:7. If ∠ cod = 15 ゜, calculate the degree of ∠ AOB

Suppose ∠ AOB = x ゜, ∫ ray OC divides ∠ AOB into two parts: 1:3, ∫ AOC = 14x °. ∫ ray od divides ∠ AOB into two parts: 5:7, ∫ AOD = 512x °, and ∫ cod = ∠ AOD - ∠ AOC, ∫ cod = 15 °, ∫ 15 = 512x-14x, ∫ x = 90, i.e. ∫ AOB = 90 °

As shown in the figure, the ray OC is in the interior of ∠ AOD, the ray od bisects ∠ BOC, and ∠ AOC = 1 / 3 ∠ AOB, the degree of ∠ AOB is calculated by the mutual complement of ∠ doc and ∠ AOC

The ray OC is in the interior of the AOD
Therefore, AOD = cod + AOC = 90 degrees
Because ray od bisects BOC
Therefore, COD = BOD
Because ∠ AOC = 1 / 3 ∠ AOB
Therefore, cob = 2 / 3 AOB
Therefore, COD = BOD = 1 / 2 cob = 1 / 2 × 2 / 3 AOB = 1 / 3 AOB
Because ∠ cod + ∠ AOC = 90 degrees, ∠ cod = 1 / 3 ∠ AOB, ∠ AOC = 1 / 3 ∠ AOB
Therefore, COD + AOC = 1 / 3 AOB + 1 / 3 AOB = 2 / 3 AOB = 90 degrees
Therefore, AOB = 135 degrees