i. From the figure, by measurement,
l(AB) = 4 cm
Now, in right-angled triangle ABC,
l(AB)2 + l(BC)2 = (4)2 + (3)2
= 16 + 9
∴ l(AB)2 + l(BC)2 = 25 …. (i)
l(AC)2 = (5)2 = 25 ….(ii)
∴ From (i) and (ii),
l(AC)2 = l(AB)2 + l(BC)2
∴ Pythagoras’ theorem is verified