Question

find the area of ring between two concentric whose circumference are 75 cm and 55 cm.​

Answer 1

Answer:

84cm

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Answer 2

$\huge\mathfrak\red{Answer}$

We have the circumference of two concentric circles 75cm and 55cm

$\bold{we \: know \: that \: circumference \: of \: a \: circle \: is \: given \: by = > \: 2\pi \: r}$

$=>2×722×r=75 \\ =>r=4475×7 \\ =>r=44375 \\ =>r=8.5cm$

So, in 1 st case 2πr = 75 cm

Similarly, in 2 nd case 2πr= 55cm

$= >2πr=55 \\ =>2×722×r=55 \\ =>r=4455×7 \\ =>r=44385 \\ =>r=0.7cm$

area of the ring is as follows

$</p><p>=>area \: of \: ring=(π×r12)−(π×r22) \\ </p><p></p><p>= > \green{area \: of \: \:ring \: = } \bold({ \frac{22}{7} \times (8.5)^{2} \times} ) - ( \frac{22}{7} \times (0.7)^{2} )</p><p></p><p>$

$=>areaofthering=(22 \div 7×72.25)−(22 \div 7×0.49)$

$</p><p></p><p>\begin{gathered}= > \green{area \: of \: the \: ring = } \bold{ \frac{1509.5}{7} - \frac{10.78}{7} } \\ \\ = > \green{area \: of \: the \: ring = } \bold{215.6 - 1.5}\end{gathered} \\ </p><p></p><p>= > \boxed{\green{area \:of \:the \: ring = } \bold{ \red{214.1m ^{2} }}}</p><p></p><p>$