Jawabanmu

2014-09-12T19:14:30+07:00
A. l. lingkaran = π r2 = 22/7 x 7 x7 = 154 cm2
b.2 π r t = 2x22/7x 7 x 10= 440 cm2
c.π r2 + 2 π r t = 22/7 x 7 x 7 + 2 x 22/7 x 7 x 10 = 154 + 440 = 594 cm2
d.= 2 π r (r + t) = 2 x 22/7 x 7 ( 10 + 7 ) = 44 x 17 = 748 cm2