Step-by-step explanation:
it seems the answer is four (option a)
In an isosceles triangle that has exactly two equal sides, the equal sides are called legs and the third side is called the base. The angle included by the legs is called the vertex angle and the angles that have the base as one of their sides are called the base angles.
Let
and
. By the product rule,

By the power rule, we have
and
, but
are functions of
, so we also need to apply the chain rule:


and we have


So we end up with

Replace
to get everything in terms of
:

We can simplify this by factoring:


Answer:
30
Step-by-step explanation:
If CUB is 78 and that’s the full angle just to 48 minus 78 and you get your answer.