Jawabanmu

2014-05-16T11:23:05+07:00
La= s.s
     =20.20 =400

Lsegitiga= 1/2.a.t
                =1/2.20.24 = 240 x 4 =960

400+960= 1360
2014-05-16T12:00:21+07:00
L alas = ( 20 x 20 ) =400  cm^{2}  

t sisi tegak =  \sqrt{ 26^{2} -  10^{2}  }
                 =  \sqrt{676 - 100} =  \sqrt{576} = 24 cm

L sisi tegak =  \frac{4 ( 20 . 24 )}{2}
                  = 2 x 480 = 960  cm^{2}  

L total = ( 400 + 960 )  cm^{2}  = 1360  cm^{2}