construim NN' _|_ PQ
in Δ dreptunghic NPQ N'N² = N'Q·N'P = 16·9 NN' = MQ = 12 cm
( N'Q = MN = 16cm; N'P = PQ - QN'= 9cm)
in Δ NN'P NP² = N'N² + N'P² = 144 + 81 = 225 NP = 15 cm
a) P = 16 + 15 + 25 +12= 68cm
b) A = (B + b)·h /2 = (25+16)·12/2 = 41·6 = 246cm²