In Δ RST (See Fig. 9.51), what is value of x ?

In

ROT + RTO + TRO = 180o


140o+ b + a = 180o


a + b = 40o (i)


In


RST + SRT + STR = 180o


x + a + a + b + b = 180o


x + 2 (a + b) = 180o


x + 80o = 180o


x = 100o

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