Answer:
To find the mean height of all 10 children, we need to find the total height of all the children and divide it by the number of children. The total height of the four girls is 4 * 1.4 = <<41.4=5.6>>5.6m
The total height of the six boys is 6 * 1.7 = <<61.7=10.2>>10.2m
The total height of all 10 children is 5.6 + 10.2 = <<5.6+10.2=15.8>>15.8m
The mean height of all 10 children is 15.8/10 = <<15.8/10=1.58>>1.58m. Answer: \boxed{1.58}.
Explanation: