The formula&nbsp;C=2πr&nbsp;the circumference C of a circle is proportional to its radius r(a)Solve&nbsp;C=2πr&nbsp;for r&nbsp;(b) If a circle's perimeter is 15 inches, what is its radius? leave the symbol&nbsp;π&nbsp;in your answer.

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The formula&amp;nbsp;C=2πr&amp;nbsp;the circumference C of a circle is proportional to its radius r(a)Solve&amp;nbsp;C=2πr&amp;nbsp;for r&amp;nbsp;(b) If a circle&#039;s perimeter is 15 inches, what is its radius? leave the symbol&amp;nbsp;π&amp;nbsp;in your answer.

avortarF · Accepted Answer

1. The given formula is&amp;nbsp;C=2πr&amp;nbsp;where, C is the circumference of a circle. r is radius of a circle. and,&amp;nbsp;π&amp;nbsp;the ratio of circumference to diameter is always the same.Solution a:&amp;nbsp;⇒C=2πr&amp;nbsp;⇒Cπ=2πrpi&amp;nbsp;(Dividing both sides by pi)&amp;nbsp;⇒Cπ=2r&amp;nbsp;⇒C2π=2r2&amp;nbsp;(Dividing both sides by 2)&amp;nbsp;⇒C2π=r&amp;nbsp;⇒r=C2π&amp;nbsp;(Reversing both sides)&amp;nbsp;2. Solution b: the circumference of the circle is 15 inches i,e.,&amp;nbsp;C=15&amp;nbsp;Putting the value of C in 1, we get:&amp;nbsp;r=C2π&amp;nbsp;or,r=152π&amp;nbsp;(C=15)&amp;nbsp;or,&amp;nbsp;r=7.5π

The formula C=2pi r relates the circumference C of a circle to its radius r. (a)Solve C=2pi r for r (b) If a circle's circumference is 15 inches, what is its radius? leave the symbol pi in your answer.

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