∠BDC=30, so ∠CBD + ∠BCD=180-30=150
ΔDBC is isosceles, so ∠CBD=∠BCD=half of 150=75
∠ABC=∠ABD-∠CBD=155-75=80
ΔABC is isosceles, so ∠ABC=∠ACB=80
∠BAC=180-80-80=20
Option B:
is the correct answer.
Explanation:
The exponential equation is 
If
, then 
Thus, the equation becomes

Applying log rule,
and thus the equation becomes

Since, we know that,
, using this we get,

Hence, the logarithmic equation which is equivalent to the exponential equation
is 
Thus, Option B is the correct answer.
So this first wants you to find where sin is √3/2 when θ is between π and 3π/2. θ would therefore be located at 2π/3.
Now plug in the value of θ for cosine:
cos (2π/3) = -1/2
And tangent:
tan (2π/3) = -√3/3
Solution:
The probability of an event is expressed as

In a pack of 52 cards, we have

Thus, we have the probability to be evaluated as
-- Kenny's weight is 6/7 of Melvin's weight.
-- Melvin's weight is 7/7 of Melvin's weight.
-- The ratio of Kenny's weight to Melvin's weight is (6/7) / (7/7) = 6/7 .