Question 519980
Area of triangle = (base * height)/2

We have been given

Area of triangle = 8.4 sq m
height = 4.8 m
base = ?

a = (b*h)/2
Multiply by 2 both sides
2a = bh
2a/h = bh/h
2a/h=b
b=2a/h
Plug in the values of a, h in above equation

b = 2*(8.4) / 4.8
b = 16.8/4.8
b = 3.5 m

Length of base is 3.5 meter.