In a right triangle, prove that the line segment joining the mid-point of the hypotenuse to the opposite vertex is half the hypotenuse.
Given: ABC is right angle triangle
D is the midpoint of AC
Construction: Construct EC parallel to AB, and AE parallel to BC. Join DE.
To prove:
Proof:
In ADB and
EDC
AD = CD (D is midpoint)
BD = DE (D is midpoint)
ADB =
EDC (Vertically opposite angles)
ADB
EDC (by SAS congruence)
AB = EC (by CPCT)
Now, ABC +
BCE = 180°
=> 90° + BCE = 180° (
ABC = 90°, Given)
=> BCE = 90°
And EC || AB (
BAD and
DCE are alternate angles)
In ABC and
EBC
BC = BC (common)
AB = EC (From above)
ABC =
BCE (From above)
ABC
ECB (by ASA congruence)
AC = EB (by CPCT)
Hence proved