Answer:
Equilateral triangle
Step-by-step explanation:
sum the parts of the ratio, 12 + 6 = 18 parts
exterior angle + interior angle = 180°
180° ÷ 18 = 10° ← value of 1 part of the ratio , then
6 parts = 6 × 10° = 60° ← interior angle
12 parts = 12 × 10° = 120° ← exterior angle
The sum of the exterior angles of a polygon = 360°
Divide 360° by 120° to find number of sides
360° ÷ 120° = 3
and since the interior angles are 60° , then
polygon is an equilateral triangle
