5 km = 5000 m
S length =ab
= 1.8*5000
=9000 square meters
S step =(a+b)h/2
=(200+350)* 100/2
=550* 100/2
=55000/2
=27500 square meters
27500/9000 is approximately equal to 3. 1 (hour).
A: It takes about 3. 1 hour.
p97 2
S triangle =ah/2
= 1.2*5/2
=6/2
=3(㎡)
S length =ab
=4*5
=20(㎡)
S wall =s triangle +s length
=3+20
=23(㎡)
23* 185=4255 (block)
A: 4,255 bricks were used.
Right? If not, tell me what the problem is.