Răspuns :
At= ? At = pi· R( G+ R)
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R= 4 At= pi·4( 5+ 4)
G = 5
At = pi·4·9
At = 36 pi cm²
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R= 4 At= pi·4( 5+ 4)
G = 5
At = pi·4·9
At = 36 pi cm²