Answer:
base= 2 cm
Step-by-step explanation:
A=1/2bh
(1/2x)40=1/2b(10)x(1/2)
20=b(10)/10
2=b
base = 8 cm
A= 1/2bh
40=1/2*b*10
40/ 1/2= 80
80/10= 8
b=8