Draw △ABC as shown in the figure with following steps.
Draw a line BC = 3 cm.
At point C, draw a line at 80° angle with BC.
Take an arc of 4 cm from point C, which will cut the line at point A.
Now, join AB, it will be approximately 4.5 cm.
AC2 + BC2 = 42 + 32
= 9 +16
= 25
AB2 = 4.52
= 20.25
AB2 not equal to AC2 + BC2
Therefore here AB2 < AC2 + BC2