Points M and N are the midpoints of sides AB and BC of triangle ABC side AC is 42 Find MN.

Given:
triangle ABC,
points M – the middle of side AB,
point N – midpoint of the aircraft side,
AC = 42 centimeters.
Find the length of the segment МN -?
Solution:
Consider the triangle ABC. Since the points M and N are the midpoints of the sides AB and BC, therefore the segment MN is the middle line of the triangle ABC.
Then MN = 1/2 * AC;
MN = 1/2 * 42;
MN = (1 * 42) / 2;
MN = (1 * 21) / 1;
MN = 21 centimeters.
Answer: 21 centimeters.