In aΔ ABC if 3 ∠A = 4∠B = 6∠C, then the value of ∠A =
Answer: (b) 80o
3ÐA = 4ÐB = 6ÐC (Given)
Then, ÐB = 3/4 ÐA & ÐC = 3/6 ÐA => ÐC = ÐA/2 ………………..(1)
As, we know that the sum of all angles of a triangle is 180o.
Then, ÐA + ÐB + ÐC = 180o
From equation (1),
ÐA + 3/4 ÐA + ÐA/2 = 180o
(4 ÐA + 3 ÐA + 2 ÐA)/4 = 180o
9 ÐA = 180 x 4
ÐA = 720/9
ÐA = 90o
Then, the value of ÐA will be 80o.
Hence, the correct answer is option (b) 80o.