The inner circumference of a ring is 31 4cm, and the width of the ring is 2cm.

Inner Diameter:

Inner radius 10 2 = 5cm

The outer radius is 5 + 2 = 7 cm

Ring area: (7 7-5 5).

The radius of the inner circle is:

The radius of the outer circle is: 5+2=7cm

Then the area of the ring is: square centimeters.

The diameter of the inner circle d= radius r=d 2=10 2=5cm, then the radius of the outer circle r=r=2=5+2=7cm

Annular area s = outer circle area s - inner circle area s inside.

Divide by centimeters.

10 + 2 * 2 = 14 cm.

14 divided by 2 = 7 centimeters.

Cm.

Divide by 2 = 5

r:5+2=7

of the square - 5 of the square).

The radius of the outer banquet front is frank and centimeter.

Inner radius 5-3 = 2 cm.

The area is squared and centimeters.

Analysis: The circumference of the ring is equal to the sum of the outer and inner circumferences. However, according to the calculation, the circumference of the outer circle of the ring is, so the unavoidable energy in the title is the circumference of the ring, which should be the circumference of the inner circle of the ring.

The radius of the outer circle = 12 2 = 6 (cm).

Radius of the inner circle = perimeter Pi 2=

Annular area = outer circle area - inner circle area = circumferential equilibrium x (square of outer circle radius - square of inner circle radius).

A: The area of this ring is a square centimeter.

Circumference = 2 r 2r = d = 10cm s= (12 2) Hu Xi - 10 2).

Look at the value of your mountain dust, and take the teasing Zen into.

The radius of the outer circle is 40 2=20 (cm).

The radius of the inner circle is 20 5 = 15 (cm) the area of the ring is noisy) = square centimeters).

The area of the inner circle is square centimeters).

Answer: The area of the ring is centimeters squared, and the area of the inner circle is centimeters square.

The radius of the great circle is 4+1=5

The area of the great circle is squared and the square is equal to 25.

Small circle area 16 system.

The large circle reduces the chain and contains the circle equal to 9 factions.

So the circumferential area is 9 pies.

Inner Ring Semi-Disturbance Weijing Liquid Napei 7 Outer Ring Radius 7 + 2 = 9 Large Circle Surface Sensitive Closed Product = Small Circle Area Ring Area =

Great circle radius: (

Small circle radius: (

Annular area: *5*5- *4*4=9 = square centimeters) If there are new questions, please do not ask the form of the ridge of the cavity of the Yuancha cavity, send another question and ask me for help or send the question link address at the follow-up place, yours is the driving force of my service.

The radius of the inner circle is r=7cm, and the radius of the outer circle is r=7+2=9cm, so the area of the ring = the area of the outer circle - the area of the inner circle = r 2- r 2= (9 2-7 2) = 32 square centimeters.

The radius of the inner town sales and rent circle is.

The radius of the outer omen circle is.

5+2=7(cm)

The area of the ring is searched for.

Cm.