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In a Delta ABC, angle C = 3 angle B...

In a ` Delta ABC, angle C = 3 angle B = 2 (angle A + angle B)`, then ` angle B ` = ?

A

`20^(@)`

B

`40 ^(@)`

C

` 60 ^(@)`

D

`80^(@)`

Text Solution

Verified by Experts

The correct Answer is:
B
Let `C = 3B = 2(A+B) = x ^(@)`
Then, `C = x ^(@), B = ((x)/(3))^(@) and (A + B) = ((x)/(2)) ^(@)`.
`(A + B) +C = 180^(@) rArr (x)/(2) + x = 180 rArr 3x = 360 rArr x = 120 `.
` therefore angle B = ((120)/(3))^(@) = 40 ^(@)`
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