2: base = 3 cm height = 2 cm. A = 0.5 x 3 cm x 2 cm = 3 cm2 ... A = 0.5 x 4 cm x 1 cm = 2 cm2. Triangle no. 5: ... 1/4 (3.14 x 4.5 cm x 4.5 cm) = 15.9 cm2 ...
確定！ 回上一頁
