Download - Revision: Circles

P6 MATHS

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Taken from Learning Maths Book 6B

Revision: Circles

Do these word problems. Show your working clearly in the space provided.

1. Asemicircleandaquadrantareenclosedinarectangleasshownbelow.Findtheareaoftheshadedpart.(Takeπ=3.14)

10cm

10cm

O

2. Thefigurebelowshowstwoidenticalcirclesandarectangle.Theradiusofeachcircleis28

cm. Findtheareaoftheshadedpart.(Takeπ= 22___ 7 )

O O

3. Thefigurebelowshowsasemicircleandthreeidenticalquadrantsremovedfromasquare.Thelengthofthesquareisfourtimesthediameterofthesemicircle.(Takeπ=3.14)

(a) Findtheareaoftheshadedpart.Roundoffyouranswertothenearestwholenumber.

(b) Find theperimeterof the shadedpart. Roundoff youranswer to thenearestwholenumber.

5cm 5cm

5cm

5cm

P6 MATHS


1. Areaoftherectangle=30×20=600cm2

Areaofthesemicircle= 1__ 2 ×�r2= 1__ 2 ×3.14×10×10=157cm2

Areaofthequadrant= 1__ 4 ×�r2= 1__ 4 ×3.14×10×10=78.5cm2

600–157–78.5=364.5cm2

Theareaoftheshadedpartis364.5 cm2.

2. Areaoftherectangle=(2×28)×28=1568cm2

Areaofeachquadrant= 1__ 4 ×�r2= 1__ 4 × 22___ 7 ×28×28=616cm2

1568–616–616=336cm2

Theareaoftheshadedpartis336 cm2.

3. (a) Lengthofthesquare=4×5=20cm

Areaofthesquare=20×20=400cm2

Areaofthesemicircle= 1__ 2 ×�r2= 1__ 2 ×3.14× 5__ 2 × 5__ 2 =9.8125cm2

Areaofeachquadrant= 1__ 4 ×�r2= 1__ 4 ×3.14×5×5=19.625cm2

400 – 9.8125 – (3 × 19.625) = 331.3125 ≈ 331 cm2

Theareaoftheshadedpartis331 cm2.

(b) Circumferenceofeachquadrant= 2�r___ 4 = 2×3.14×5___________ 4 =7.85cm

Circumferenceofthesemicircle= �d___ 2 = 3.14×5________ 2 =7.85cm

7.85 + 10 + 7.85 + 10 + 7.85 + 10 + 7.85 + 15 = 76.4 ≈ 76 cm

Theperimeteroftheshadedpartis76 cm.

Solutions to Revision: Circles



P6 MATHS




Revision: Pie Charts

Write your answers on the lines provided.

Thepiechartbelowshowsthedifferentactivitiesthataclassofstudentsenjoysdoingduringfreetime.Studyitcarefullyandanswerquestions1to3.

Jogging

Reading

Collectingstamps

Watchingmovies

25%

15%

Cycling

30%

1. If12studentslikecycling,howmanystudentsarethereintheclass?

2. Howmanystudentslikewatchingmovies?

3. Ifthenumberofstudentswholikereadingistwicethenumberofstudentswholikejogging,howmanystudentsliketoread?

1.40 students30%→1210%→12÷3=4

100%→10×4=40

2.10 students 25 ___ 100×40=10

3.8 students100%–25%–15%–30%=30%20%ofthestudentslikereading.

20 ___ 100×40=8

Solutions:

P6 MATHS




Revision: Pie Charts

Do these word problems. Show your working clearly in the space provided.

Thepiechartbelowshowsthenumberoffruitsoldbyashopkeeper.Studyitcarefullyandanswerquestions1and2below.

Papayas

Watermelons

20%

Bananas

Starfruit

25%

1. Iftheshopkeepersold300fruitaltogether,howmanywatermelonsdidhesell?

2. Howmuchmoneywouldhemakefromthesaleofstarfruitandpapayas ifhesoldeachstarfruitat$1.30andeachpapayaat$1.60?

1.100%–20%–25%–25%=30%

30 ___ 100 ×300=90

Hesold90watermelons.

2. 25 ___ 100 ×300=75

Hesold75starfruit.

20 ___ 100×300=60

Hesold60papayas.(75×$1.30)+(60×$1.60)=$193.50Hewouldmake$193.50.

Solutions:

P6 MATHS



Taken from Mental Mathematics Book 6

Mental Maths: GENERAL REVISION 18

Do these sums mentally.

1. 64÷1 1__3 =

2. 882=

3. √_______

17161 =

4. 3√_______

42875 =

5. 347×99=

6. 49×111=

7. 33 1__3 %of174=

8. 182×429=

9. 212–202=

10. 17+18+19+20+21+...+54=

Solutions:1.482.77443.1314.355.343536.54397.588.780789.4110.1349