Answer: 4m
Explanation:
Note : midpoints divide a line into two equal parts.
To calculate the length of SA;
We can consider the large triangle QRS with
Two midpoints :
A on the line QS, QA = 4m ;
and B on the line RS with RB = 3m
Fron the definition of midpoint :
QS = QA + AS
where QA = AS
QS = 2QA = 2AS
Therefore,
QA = QS
4m = 4m