Answer:
Since this is an isosceles triangle, the angles opposite to the equal sides will also be equal
Therefore,
angle ABC = angle ACB
We are given that angle ACB is 30 degrees
Hence, angle ABC = 30 degrees
We know that according to the angle sum property, the sum of all interior angles of a triangle is 180 degrees
So, angle ABC + angle ACB + angle CAB = 180 degrees
replacing the variables with values we already know
30 + 30 + angle CAB = 180
angle CAB = 180 - 60
angle CAB = 120 degrees
Hence the measure of angle A is 120 degrees
