AIR TEMPERATURE READING



GRADE V CIRCUMFERENCE OF A CIRCLEObjective:Derive the formula for the circumference of a circle Find the circumference of a circle in cm/m.REVIEWFrom the previous lessons you learned that the perimeter refers to the distance around a polygon. You were also taught how to find the perimeter of certain polygons. Calculate the perimeter of each polygon below. Write the answer in your notebook.33 cm1)2)70 cm28 cm24 cm24 cm26 cm26 cm3)4)29 cm30 cm30 cm30 cm30 cm27 cm28 cm28 cm28 cm28 cm27 cm22 cm29 cm5) What is the perimeter of a regular pentagon whose sides measure 15 cm?Php1.000 cm?APhp1.0010203040506070A?STUDY AND LEARNDo this simple activity with anybody in your home. Procedure:Get a five-peso coin, one-peso coin, and a twenty-five centavo coin or a tansan.Measure their diameters in cm using a ruler. Record them under Diameter.CoinDiameter (D)Circumference (C)Ratio of C:DQuotient of C/DPhp5Php1Php0.25Take the one peso coin. Mark point A on the edge of the coin.Tape a meter stick or tape measure on top of a table.Put point A of the coin on 0cm on your meter stick or tape measure.Roll your coin along the meter stick or tape measure until point A touches the ruler again. (Make sure that it rolls and does not slide).Get the distance covered by the rolling of the coin on the meter stick or tape measure. Record this under “Circumference.”Repeat the same procedures using the other coins.cm meter stick or tape measureHere is the expected result of your activity. Don’t worry if your answer is not exactly the same as the expected results. What do you think is the explanation behind the difference?CoinDiameter (D)Circumference (C)Ratio of C:DQuotient of C/DPhp526 mm81.64 mm81.64 : 263.14Php123 mm72.22 mm72.22 : 233.14Php0.2519 mm59.66 mm59.66 : 193.14The distance covered by the rolling coin is the length around the circle. We call this the circumference of the circle.The quotient of the circumference to the diameter is found in the last column of the table.The quotient of the circumference to the diameter of a circle is the same for any circle and is equivalent to the value of ? which is approximately 3.14.? is spelled pi and read as “pie.”This number is approximately 3.1416 orSince ? = C → circumferenced → diameter22 .7and d = 2r then C = ?d or C = 2?r where d is the diameter and r is the radius.15 cm ?A8 cm?BLet us use this formula in calculating the circumference of the circles A & B below.1)2)C = ?d (since the diameter is given in the first circle)= 3.14 x 15 cm= 47.10 cmC = 2?r (since the radius is given in the second circle)= 2(3.14 x 8 cm)= 50.24 cmTRY THESEDo what is asked.A circular flower garden has a diameter of 10 meters. What is the circumference of the flower garden?Carla has a circular tablecloth. Its radius is 1.5 m. What is its circumference?3. d = 15 cmC = 4. r = 9 cmC = 5. d = 25 cmC = WRAP UPThe circumference of a circle is the distance around the circle. To get the circumference of a circle, use any of the following formulas.C = ?d (if the diameter is given) C = 2?r (if the radius is given)ON YOUR OWNFind the circumference of the circle with the given diameter or radius. Write your solutions and answers in your notebook.d = 17 cmd = 13 cm 3. r = 6.15 m 4. d = 8.5 cm 5. r = 2.25 cm ................
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