三角形的底是7厘米,高是2厘米,它的面积是 ,和它等底等高的平行四边形的面积是 .
0.25=4÷ = :4= %= 折.
÷8==0.375=9÷ =.
= ÷ =9: == %= 折.
= ÷ = (填小数)
12÷ =0.75== :36= %