RAYAT SHIKSHAN SANSTHA’S SHRIMAN SHETH GANPATRAO SURYAWANSHI VIDYALAYA TAMBAVE TAL. PHALTAN DIST SATARA

THE CIRCUMFERENCE AND AREA OF A CIRCLE SUB- MATHEMATICS STD- 8th TOPIC THE CIRCUMFERENCE AND AREA OF A CIRCLE

CIRCUMFERENCE OF A CIRCLE C=2πr C= CIRCUMFERENCE OF A CIRCLE π=22/7 0R 3.14 r = RADIUS OF A CIRCLE

THE RELATION BETWEEN DIAMETER AND RADIUS OF A CIRCLE d=2r d= Diameter of a circle r= Radis of a circle

The ratio circumference to diameter of any circle remains constant and that is 22/7 or 3.14 c/d=π =22/7 or 3.14

PROBLEMS BASED ON CIRCUMFERENCE OF A CIRCLE Q. THE RADIUS OF A CIRCLE IS 14cm. FIND THE CIRCUMFERENCE OF THE CIRCLE ? SOLUTION- GIVEN- r= 14cm π= 22/7 c = ? FORMULA C=2πr =2*22/7*14 =2*22*2 =88 cm HENCE CIRCUMFERENCE OF A CIRCLE= 88cm

Q. IF THE CIRCUMFERENCE OF A CIRCLE IS 176m Q.IF THE CIRCUMFERENCE OF A CIRCLE IS 176m. THEN FIND THE RADIUS OF THE CIRCLE. SOLUTION- GIVEN- C= 176m π= 22/7 r= ? FORMULA C=2πr 176 =2*22/7*r 176*7 =44*r 1232/44 =r 28 =r HENCE RADIUS OF A CIRCLE=28m

AREA OF A CIRCLE A=πr2 A=AREA OF A CIRCLE π= 22/7 or 3.14 r= RADIUS OF A CIRCLE

IF RADIUS OF A CIRCLE IS 7CM. THEN FIND THE AREA OF THAT CIRCLE. SOLUTION R= 7cm Π= 22/7 FORMULA A=πr2 = 22/7*(7)2 = 22/7*49 = 22*7 = 154 sqcm. HENCE THE AREA OF THE CIRCLE IS 154sq.cm

IF THE AREA OF A CIRCLE IS 154sq.cm THEN FIND THE RADIUS OF THE CIRCLE . SOLUTION A= 154sq.cm Π = 22/7 R = ? FORMULA A=πr2 154 =22/7*(r)2 154*7 =22*(r)2 1078 = 22*(r)2 1078/22=(r)2 49=(r)2 7=r HENCE THE RADIUS OF THE CIRCLE IS 7 cm.

IF CIRCCUMFERENCE OF A CIRCLE IS 88cm THEN FIND THE AREA OF A CIRCLE. C= 88cm A= ? FORMULA C = 2πr 88 = 2*22/7*r 88*7 = 44*r 616/44 = r r= 14cm A=πr2 = 22/7*(14)2 = 22/7*196 = 22*28 = 616 sqcm. HENCE THE AREA OF THE CIRCLE IS 616 sq.cm

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