Question

The circle formed by the blades of a fan has a circumference of eighty-one and five-sevenths inches. What is its diameter? Use twenty-two sevenths for pi.

twelve inches

eighteen inches

twenty-one inches

twenty-six inches

Answer 1

@ganymede

Answer 2

diameter * pi = cicumference

Answer 3

\[\frac{ circumference }{ \pi } = diameter\]

Answer 4

81 * 7 = 567, 567+5 = 572, so 81 and 5/7 can be re-written 572/7

Answer 5

\[\frac{ \frac{ 572 }{7} }{ \frac{ 22 }{ 7}}\]

Answer 6

so 26 in.

Answer 7

yep