Final answer:
Each base angle in the isosceles triangle measures 50 degrees, found by subtracting the given vertex angle from the total sum of angles in a triangle and then dividing by two, as the base angles in an isosceles triangle are equal.
Step-by-step explanation:
In an isosceles triangle, the measure of the angle formed by the two congruent sides is given as 80 degrees. Recall that an isosceles triangle has two equal sides and consequently two equal base angles. According to the triangle sum property, the sum of the angles in any triangle is always 180 degrees.
To find the measure of each base angle in this isosceles triangle, we can subtract the given angle from 180 degrees and then divide by 2, because the two base angles are congruent (equal in measure).
So, we have:
Total sum of angles = 180 degrees
Given vertex angle = 80 degrees
Sum of base angles = 180 degrees - 80 degrees = 100 degrees
Each base angle = 100 degrees / 2 = 50 degrees.
Therefore, each base angle in this isosceles triangle measures 50 degrees.