Answer:
(a) -2.3°/min
(b) -2.9°/min
Explanation:
The average rate of change is the ratio of the difference in R values to the difference in the corresponding t values.
(a) m = (157.6 -226.6)/(30 -0) = -69/30 = -2.3 . . . degrees per minute
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(b) m = (61.6 -119.6)/(70 -50) = -58/20 = -2.9 . . . degrees per minute