8th Class Mathematics Sample Paper Mathematics Sample Paper - 8

  • question_answer
    The shape of a garden is rectangular in the middle and semicircular at the ends as shown in the diagram. Find the area and perimeter of this garden. [Length of rectangle is \[20-\left( 3.5\text{ }+\text{ }3.5 \right)\]meters]

    Answer:

    Length of rectangle \[=20-\left( 3.5+3.5 \right)\]
    \[=20-7=13m\]
    Breadth of rectangle = 7 m                                                                                                           
    The area of rectangular \[=l\times b=13\times 7=91\,{{m}^{2}}\]
    The perimeter of rectangular part \[=2\left( \text{l}\,\text{+}b \right)\]
    \[=2\left( 13+7 \right)=40m~\]   
    Now,       radius of each semicircle = 3.5 m
    The area of both semicircular part \[=\pi {{r}^{2}}\]
    =\[=\frac{22}{7}\times 3.5\times 3.5\]
    = 38.5m2
    The perimeter of both semicircular \[=2\pi r\]
    \[=2\times \frac{22}{7}\times 3.5=22m\]
    \[\therefore \]The area of whole garden=The area of rectangular part
    + The area of semi-circular part
    \[=91{{m}^{2}}+38.5{{m}^{2}}\]
    \[=\text{ }129.5{{m}^{2~}}\]
    The perimeter of whole garden = The perimeter of rectangular part
    + The perimeter of semi-circular part
    = 40 m + 22 m
    = 62 m.


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