Annulus

The radius of the larger circle is 8cm, the radius of smaller is 5cm. Calculate the contents of the annulus.

Correct result:

S =  122.522 cm2

Solution:

r1=8 cm r2=5 cm  S1=π⋅ r12=3.1416⋅ 82≐201.0619 S2=π⋅ r22=3.1416⋅ 52≐78.5398 S=S1−S2=201.0619−78.5398=122.522 cm2r_{1}=8 \ \text{cm} \ \\ r_{2}=5 \ \text{cm} \ \\ \ \\ S_{1}=\pi \cdot \ r_{1}^2=3.1416 \cdot \ 8^2 \doteq 201.0619 \ \\ S_{2}=\pi \cdot \ r_{2}^2=3.1416 \cdot \ 5^2 \doteq 78.5398 \ \\ S=S_{1}-S_{2}=201.0619-78.5398=122.522 \ \text{cm}^2

Try another example


Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!


Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




You need to know the following knowledge to solve this word math problem:


 
We encourage you to watch this tutorial video on this math problem: video1

Next similar math problems:

  • Annulus
    medzikruzie Calculate the area of two circles annulus k1 (S, 3 cm) and k2 (S, 5 cm).
  • 22/7 circle
    red_circle Calculate approximately area of a circle with radius 20 cm. When calculating π use 22/7.
  • Circle area
    circle3 Calculate the circle area with a radius of 1.2 m.
  • Circle - easy 2
    circle_3 The circle has a radius 6 cm. Calculate:
  • Bicycle wheel
    cyklo2_2 After driving 157 m bicycle wheel rotates 100 times. What is the radius of the wheel in cm?
  • Two circles
    two_circles Two circles with a radius 4 cm and 3 cm have a center distance 0.5cm. How many common points have these circles?
  • Cable
    wire Cable consists of 8 strands, each strand consists of 12 wires with diameter d = 0.5 mm. Calculate the cross-section of the cable.
  • Diameter to area
    circle_eq_1 Find the area of a circle whose diameter is 26cm.
  • Sidewalk
    kruhovy-objazd The city park is a circular bed of flowers with a diameter of 8 meters, around it the whole length is 1 meter wide sidewalk . What is the sidewalk area?
  • Clock hands
    clocks2_16 The second hand has a length of 1.5 cm. How long does the endpoint of this hand travel in one day?
  • Circle - simple
    kruh The circumference of a circle is 198 mm. How long in mm is its diameter?
  • Area of ditch
    prikop How great content area will have a section of trapezoidal ditch with a width of 1.6 meters above and below 0.57 meters? The depth of the ditch is 2.08 meters.
  • Equation 29
    eq222_18 Solve next equation: 2 ( 2x + 3 ) = 8 ( 1 - x) -5 ( x -2 )
  • Pizza 4
    pizza_6 Marcus ate half pizza on monday night. He than ate one third of the remaining pizza on Tuesday. Which of the following expressions show how much pizza marcus ate in total?
  • Negative in equation
    eq1_7 2x + 3 + 7x = – 24, what is the value of x?
  • Write 2
    fractions_12 Write 791 thousandths as fraction in expanded form.
  • Rounding
    approx The following numbers round to the thousandth: