10th Class Mathematics Solved Paper - Mathematics 2017 Delhi Set-I

  • question_answer
    A chord PQ of a circle of radius 10 cm subtends an angle of \[60{}^\circ \] at the centre of circle. Find the area of major and minor segments of the circle.

    Answer:

    \[r=10\text{ }cm,\text{ }i=60{}^\circ \]
    Area of minor segment \[=\frac{\theta }{360}\times \pi \,\,{{r}^{2}}-\frac{1}{2}{{r}^{2}}\,\,\sin \,\,i\]
                \[=\frac{60}{360}\times 3.14\times 10\times 10-\frac{1}{2}\times 10\times 10\,\,\sin \,\,60{}^\circ \]
                \[=\frac{1}{6}\times 3.14\times 100-\frac{1}{2}\times 100\times \frac{\sqrt{3}}{2}\]
                \[=\frac{314}{6}-\frac{100}{4}\times 1.73\]
                \[=\frac{314}{6}-\frac{173}{4}=\frac{628-519}{12}=\frac{109}{12}c{{m}^{2}}\]
    Area of major segment = Area of circle\[\]Area of minor segment
    \[=\pi {{r}^{2}}-\frac{109}{12}c{{m}^{2}}=3.14\times 10\times 10-\frac{109}{12}\]
    \[=314-\frac{109}{12}=\frac{3768-109}{12}=\frac{3659}{12}c{{m}^{2}}\]


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