The ratio of the area of a sector of a circle to the area of the circle is 1 : 4. If the area of the circle is 154 $$cm^{2}$$Â , the perimeter of the sector is
area of the circle = $$ \pi r^2 = 154 $$
$$ \frac{22}{7} \times r^2 = 154 $$
on solving r =7
angle subtended by the sector at the centre = $$ 90^\circ $$
length of an arc = $$ \frac{\pi r \theta}{180} $$
            = $$ \frac{22}{7} \times 7 \times \frac{90}{180} = 11 $$
perimeter of sector = $$ 2r + l = 2 \times 7 + 11 = 25 $$Â
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