Step by step
The question
Question: in a right triangle the hypotenuse B C is 10: find the median A M to the hypotenuse.
1 Use the semicircle rule
The right angle is at A.
The median A M goes to M, the middle of the hypotenuse B C.
Draw the circle with B C as its diameter.
The angle in a semicircle is 90°, so A is on this circle too.
M is the center.
M A, M B and M C are all radii: all the same length.
2 Half the hypotenuse
The radius is half the diameter: 10 divided by 2 is 5.
Careful!
This works for the median to the hypotenuse of a right triangle.
Not for any median.
3 Check
Let's check: M B and M C are 5 each, and together they make B C, 10.
So it is right!
Let's look back.
First: use the semicircle rule.
Then: half the hypotenuse.
Last: check.