Jawabanmu

2014-06-01T12:44:55+07:00
A. tinggi alas trapesium :
pake pitagoras.
t =  \sqrt{ 10^{2}  -  4^{2} } =  \sqrt{84} =  \sqrt{4 . 21} = 2 \sqrt{21}

b. L prisma = K alas . tinggi + 2 L alas
L = (7+10+10+15) 12 + 2 ( \frac{(7+15)2 \sqrt{21} }{2}  = 22 \sqrt{21} )
L = 42 . 2 + 2 .  22 \sqrt{21}
L = 504 + 44 \sqrt{21}