A:3
B:4
C:5
D:6
如图,一桥拱的形状为抛物线,该抛物线拱的高为h=6m,宽为b=24m,则该抛物线拱的面积为____ m2.
6×8=____ 2×8=____ 8×8=____
13-9=( )