Each side of a triangle has to be shorter than the sum of the other 2. The only possible answer is b: 3,5,7 (7<5+3)
<u>Part a) </u>
we know that
An isosceles triangle has two base angles that are congruent
The sum of two base angles plus the vertex angle is equal to
degrees
so
In this problem



Solve for x




therefore
<u>the answer part a) is</u>
the value of x is 
<u>Part b)</u> What is the measure of each base angle?
we know that

we have that

substitute the value of x in the equation


therefore
<u>the answer part b) is </u>
the measure of each base angle is 