Jawabanmu

2014-09-11T19:13:05+07:00
L = ( 42 + 18 ) / 2 . 24
= 60 / 2 . 24
= 30 . 24 
= 720 cm2
2014-09-11T19:18:09+07:00
L.Trapesium = (a+b) x t ÷ 2
(42+18) x 24 ÷ 2
= 60 x 24 ÷ 2
=  1440 ÷ 2
= 720 cm²