ABSTRACT
Problem 2. In Figure 10.3, find the length of EF
By Pythagoras’s theorem: e2 = d2 + f 2 Hence, 132 = d2 + 52
169 = d2 + 25 d2 = 169 − 25 = 144
Thus, d = √144 = 12 cm i.e. d = EF = 12 cm DEF is a 5, 12, 13 triangle, another right-angled triangle which has integer values for all three sides.
