The medians AD and BE of the triangle with vertices A (0, b), B (0, 0) and C (a, 0) are mutually perpendicular, if
b=2a
a=±2b
b=−2a
a=−2b
The coordinates of D and E are (a/2, 0) and (a/2, b/2) respectively.
Now, m1=Slope of AD=b−00−a/2=−2ba
m2=Slope of BE=b/2−0a/2−0=ba
Since AD and BE are perpendicular. Therefore,
m1m2=−1−2ba×ba=−1⇒a=±2b