Final answer:
To find the measure of ∠HGI, we need more information or a diagram. The given answer choices (21º, 15º, 8º, 10º) are not sufficient to determine the measure.
Step-by-step explanation:
In a triangle, the sum of all three interior angles is always equal to 180 degrees. This property is known as the Triangle Sum Theorem. It doesn't matter what type of triangle you have—whether it's an equilateral, isosceles, or scalene triangle—the sum of the interior angles remains constant.
To find the measure of ∠HGI, we need more information or a diagram. The given answer choices (21º, 15º, 8º, 10º) are not sufficient to determine the measure of ∠HGI.