In order to covert temperature from Kelvin to Celsius scale, we have to subtract 273 from the given value because K - 273 = °C
(a) 293 K - 273 = 20°C
(b) 470K - 273 = 197°C

∆ABC is an isosceles triangle in which AB = AC. Side BA is produced to D such that AD = AB (see Fig. 7.34). Show that ∠ BCD is a right angle.
