Presentation on theme: "BASIC GEOMETRICAL CONCEPTS CIRCLE Developed by: NARESH TANGRI KAVITA KATARIA MUKESH MITTAL."— Presentation transcript:
BASIC GEOMETRICAL CONCEPTS CIRCLE Developed by: NARESH TANGRI KAVITA KATARIA MUKESH MITTAL
CONTENTS CIRCLE CENTRE RADIUS DIAMETER CIRCUMFERENCE CHORD ARC SECTOR CENTRAL ANGLE AREA OF A CIRCLE CLICK ON EACH CONTENT POINT TO LEARN ABOUT IT OR CLICK ON NEXT NEXT
OBJECTIVES After interacting with this software the learner will be able to : Define a circle. Draw a circle. Define the diameter of the circle Define the radius of the circle Define and calculate the circumference of the circle. Define chord,sector,arc,and central angle of the circle. Calculate the radius and the diameter of the circle. Define and calculate the area of the circle. BACK NEXT CONTENTS
TARGET GROUP AGE GROUP 13 TO 15 YEARS CLASSES VII-IX BACKNEXTCONTENTS
лr r AREA OF A CIRCLE. Area of Circle= πr 2 BACK TO CONTENTS NEXT
CIRCUMFRENCE OF A CIRCLE Π CIRCUMFRENCE DIAMETER CONSTANT C D (CONSTANT) Where Π 22 7 3.14 C=Π D = 2Πr BACK TO CONTENTSNEXT
EXERCISE 3 Circumference of a circle whose radius is 3.5 cm will be: (a)11cm (b)22cm. (c)33cm. (d)44cm. Click here for answer
Example 1: Find the circumference of a circle whose radius is 14 cm. Solution: Radius =14cm. Circumference= 2 π r = 2 x 22/7x14=88cms. ILLUSTRATIONS BACK NEXT
EXERCISE 1 CHOOSE THE CORRECT ANSWER If radius or circle is doubled its circumference will (a) Remain same. (b)Become double (c) Become half (d) None of these For correct answer click hereFor correct answer click here.
Example 2 :Find the distance covered by a bicycle in 100 revolutions, if the radius of its wheel is 70 cm. Solution: Given : Radius of the wheel=7 cm. Distance covered in one revolution of the wheel =circumference of the wheel =2πr Distance covered in 100 revolutions = 440 x 100 2x22/7x70=440cm. =44000cm =440 meter BACK NEXT
EXERCISE 2 If radius of a circle is halved its area will (a)Become double of itself (b)Become half of itself (c)Become one fourth of itself. (d)Become four times of itself. For correct answer click here.
EXERCISE 4 The area of a circle whose radius 10.5cmis (a)364.5cm 2 (b)346.5cm 2 (c)355.5cm 2 (d)336.5cm 2 Click here to see answerClick here to see answer.
EXERCISE 1.Find the radius of a circle whose circumference is220cm. 2.Find the circumference of a circle whose diameter is 21cm. 3.Determine the area of a circle whose radius is 14cm. 4.Determine the area swept by minute hand of a clock in one hour,if the length of minute is 7cm. ANS.(1)35cm. (2)63cm.(3)616cm 2. (4)154cm 2. BACKNEXT
EXAMPLE :3 A horse is tied to a rope of 42 cm of length at the center of a rectangular grassy plot. How much area will it graze in one complete round trip. Solution: Radius of circular path = 42 cm Area grazed by the horse = πr 2 =22/7x42x42= 6544 cm 2 BACK NEXT
ANSWERS 1.(a) 2(c) 3(b) 4(b) BACK TO EXERCISE1 BACK TO EXERCISE 2 BACK TO EXERCISE 3 BACK TO EXERCISE 4 NEXT
ACKNOWLEDGEMENT We are sincerely thankful to SH. V.K.SODHI Sh.NARESH KAPOOR Mrs.RENU