(1) MN=MC+CN=AC/2+CB/2=6/2+4/2=3+2=5 cm
(2) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=10/2=5 cm
(3) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=AB/2=18/2=9 cm
(4) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=AB/2=a/2 cm
(5) MN=MC-CN=AC/2-CB/2=(AC-CB)/2=2/2=1cm
(1) MN=MC+CN=AC/2+CB/2=6/2+4/2=3+2=5 cm
(2) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=10/2=5 cm
(3) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=AB/2=18/2=9 cm
(4) MN=MC+CN=AC/2+CB/2=(AC+CB)/2=AB/2=a/2 cm
(5) MN=MC-CN=AC/2-CB/2=(AC-CB)/2=2/2=1cm