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(0)(\pi / 4)+(0.707)(\pi / 4)+(0)(\pi / 2) \leq \mathrm{RS} \leq(0.707)(\pi / 4)+(1)(\pi / 4)+(1)(\pi / 2) \text { so } 0.56 \leq \mathrm{RS} \leq 2.91