Sally used a pencil to trace the circular base of a drinking glass. She placed four quarters in a line across the diameter of the circle. Using a ruler, she measured the diameter of each quarter, and calculated the circumference of the glass as 29.78cm. The quarter could be used as a referent for a measure of one _______, and, according to Sally’s measurement, each quarter has a diameter of ________cm.
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Sally used a pencil to trace the circular base of a drinking glass. She placed four quarters in a line across the diameter of the circle. Using a ruler, she measured the diameter of each quarter, and calculated the circumference of the glass as 29.78cm. The quarter could be used as a referent for a measure of one _______, and, according to Sally’s measurement, each quarter has a diameter of ________cm.
C = π d
29.78 = 3.14 • d
d = 29.78 / 3.14
d = 9.48
4Q = d
4Q = 9.48
Q = 9.48 / 4
Q = 2.37 <<—— the diameter of one quarter
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