... 423+60+342+2 41, 5 =10 66,5 mm 2 18 .47 = 423 mm 2 2 8 .15 = 60 mm 2 2 (15 +23) .18 = 342 mm 2 2 21. 23 = 2 41, 5 mm 2 2 Baøi 37/ (13 0) 47 mm 18 8 15 18 21 23 S 1 = S 2 = S 3 = S 4 = 12 0m 15 0m 50m A E ... 5000 2 = 11 13 7 500 000 mm 2 = 11 13 7,5( m 2 ) Baứi 39/ (13 1) )(5,370 2 13 ).2532( 2 ).( 2 mm HCCEAB = + = + )(75 2 6.25 2 . 2 mm DKCE == S 1 = 42 cm 2 S 2 = 2cm 2 S 3 = 2 S 4 = 1, 5 S 5 = 1 S 6 ... AB.BC = 18 000 – 6000= 12 000 m 2 Bài 38/ (13 0) 12 0.50= 6 000 m 2 12 0 .15 0 =18 000 m 2 S ABCD - S EBGF = B A C D E H K 32mm 25mm 6mm AB= 32mm EC= 25mm HC= 13 mm DK= 6mm 13 mm S ABCE = S ECD = S ẹA GIAC...