Jawabanmu

2014-06-01T12:28:49+07:00
Tinggi alas segitiga :
 \sqrt{ 35^{2} -  21^{2}}  =  \sqrt{784} = 28
L permuk = K alas . tinggi + 2 L alas
L permuk = (28 + 21 + 35) 20 + 2 (28 . 21 : 2)
L permuk = (84) 20 + 2(294)
L permuk = 1680 + 588
L permuk = 2268 cm2