The formula c=3.14d can be used to approximate the circumference of a circle given its diameter. Company A manufactures and sells a certain washer with an outside circumference of 7 centimeters. the company has decided that a washer whose actual circumference is in the interval 6.9<=C<=7.1 centimeters is acceptable. Use a compound inequality and find the corresponding interval for diameters of these washers.



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