class:7                                   work sheet-3

subject: mathematics                      perimeter and area

INSTRUCTION: HOME WORK FOR APRIL SECOND AND THIRD WEEK

KEY WORDS

1)Circumference of a Circle

2)Area of Circle

Based on above video do the following sums

circumference of a circle=2𝜋r

 where 𝜋=22÷7 and r is radius of circle (d=2r)

1) Find the circumference of the circles with the following radius: (Take π = 22 ÷7 )

  

 (a) 14 cm   (b) 28 mm   (c) 21 cm 

1)Perimeter of a semi circle=(36xr)➗7 or πr+2r

2) The diameter of the given semi-circular slice of watermelon is 14 cm. What will be the perimeter of the slice of watermelon?

 Area of Circle

 1) Area of the circle = πr2

2)Area of semi circle=πr

Based on above video do the following sum

3. Find the area of the following circles, given that:

 (a) radius = 14 mm (Take π = 22/ 7 ) (b) diameter = 49 m (c) radius = 5 cm 

4) Find the area and perimeter of a semicircle of radius 7 cm. (Use π =22/7

 5) Find the area and perimeter of the figure in which PQRS is a square of side 28 cm and STR is a semicircle. (Use π = 227$\frac{22}{7}$).

)

HIGHER ORDER THINKING SKILL

.1)  A gardener wants to fence a circular garden of diameter 21 m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the costs of the rope, if it cost Rs 4 per meter. (Take π = 22 7 )

2) The difference between the circumference and the diameter of a circular bangle is 5 cm. Find the radius of the bangle. (Take π=227)

3) A girl wants to make a square-shaped figure from a circular wire of radius 49 cm. Determine the sides of a square.

4) How many times a wheel of radius 28 cm must rotate to go 352 m? (Take π = 22 7 )

5). The circumference of a circle is 31.4 cm. Find the radius and the area of the circle? (Take π = 3.14) .

 

                                              

                                                       

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