《长方形和正方形的周长》.ppt

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3、r幘?ri6 410(怀?)102 20(怀?)?怀?(6+4) 220(?r幘?ri 怀l ? maml? .a怀? ?a? ?rmam?m? 5?怀a?怀?怀? 3怀? ?aal ml ?a? ? ?rmam?m? ?r 怀? ?ma?怀 ?a?r ?怀rmam?m? ?r? 怀?怀 ?maal?怀? rmam?m? 8 怀?2?r幘r幘盀90?r幘?ri ?r?1?L ?0?a ir?10? 8?轈 ? ?1?aia ?r?r0L ?轈 ?盀aiL ?0aia?L24 8(?r幘r幘盀)8 ?r幘r幘盀 90?r幘?ri?1?:怀l ?m怀m? ?怀a? maal. ?怀?a ?i? ?

4、a? ?r?l1.?怀?1.? 怀?aa怀? ? ?rmam?m? ?l? ?l3?r幘?ri2?r幘?ri 2?r幘?ri2?r幘?ri 2?r幘?ri2+3+2+3=10 (怀?)22+32=10 (怀?) （2+3）2=10 (怀?)2.?怀? rmam?a? 1怀? ?2aal 2? ?怀1怀 ?a?l? 怀l ? ? maml .ml? ? ?maml? .? ?rmam?m? ?r maal.2 怀?1 怀?213(怀?32 6(怀?ml ? ?maml? .? ?rmam?m?6怀?子，?am?a? 15?怀a?怀?怀?8怀? ?2aal ?a?a ? ?al ?怀ar ?r 怀? ? ?怀?怀 maal. 15 怀?8 怀?821531（ 怀? ）（ 158）215 31（ 怀? ）?r? m?aa ?a?rmam?m? ?a? ?2aal2? 怀ll? 怀?l ?怀l?maal ?rmam?m?10 ?1?0?r幘r幘盀6 ?r幘r幘盀 ?i?8?轈 ?r ?8?轈r?r 00a?i拠? ?盀?轈 ?轈 ?rr?盀r? ?i拠? ?rr?盀r? ?0r ?1?L 0拠i? ?r幘r幘盀 ?盀8?轈?m怀m?:? maml? 1? .怀1怀 ?a怀? ? ?怀怀? ? 怀怀m? ? ?rmam?a? ?怀?-?怀? ?a.? ?l