1) (600 - 600) + 200 = 200
2) (600-0) + 200 = 800
S=(πD^2)/4=(3.1*40^2)/4=1240 см.кв..............
1) 1/2+1/4=2+1/4=3/4; 1/3-1/6=2-1/6=1/6; 1/4+1/8=2+1/8=3/8; 1/5-1/10=2-1/10=1/10;
2)1/2+1/4; 1/3-1/6; 1/4+1/8; 1/5-1/10; 1/6+1/12; 1/7-1/14; 1/8+1/16; 1/9-1/18