Question

In Fig, PQ||RS and a : b = 3 : 2. Then, f is equal to 

(a) 36° (b) 108° (c) 72° (d) 144°

Answer 1

(b) 108^o

From the figure, PQ||RS.

From the question it is given that, a: b = 3: 2

So, let us assume a = 3m and b = 2m

We know that, sum of angles on the straight line is equal to 180^o

Then, ∠a + ∠b = 180^o

3m + 2m = 180^o

5m = 180^o

m = 180^o/5

m = 36^o

So, a = 3m = 3 × 36^o = 108^o

b = 2m = 2 × 36^o = 72

Therefore, ∠a = ∠f = 108^o [because corresponding angles]