Article 6 (a). Bottom area = 30x30/2 = 450 volume = bottom area x height /3 = 450x20/3 = 3000 cm3. (b) Bottom area = 450Δ VAB = Δ VAC = 30x20/2 = 300VB = √ (202+302). =10 √13bc = √ (302+302) = 30 √ 2 Δ VBC height = √ ((BC/2) 2+VB2) = √1750 = 5 √ 70 Δ VBC = 30 √ 2x. 2 = 150√35 Total surface area = 450+300+150 √ 35 =1050+150 √ 35cm 2.8 (a). FH = 20 √ 2。

VH = √ ((kloc-0/0 √ 2) 2+502) =10 √ the height of 27 Δ vgh = √ ((VH) 2+102) = 20 √ 7 Δ vgh = 20 √/2 = 200 √. Total surface area of cuboid = 20x50x4+20x20x2 = 4800 Total surface area of remaining solids = total surface area of cuboid-bottom area +4 inclined planes = 4800-400+4x200 √ 7 = 4400+800 √ 7cm2.